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Alberta's numbering plan areas and area codes

Area code 403 is a telephone area code in the North American Numbering Plan (NANP) for the southern third of the Canadian province of Alberta, including the Calgary area. This numbering plan area is also served by area codes 587, 825, and 368, which form a complex overlay for all of Alberta.

History

[edit]

Area code 403 was one of nine Canadian area codes of the original North American area codes assigned by the American Telephone and Telegraph Company (AT&T) in 1947. Its numbering plan area (NPA) originally comprised the entire province of Alberta. During the course of the expansion of telephone service in the Northwest Territories and Yukon, these were serviced primarily with the same area code starting in 1960.[1][2] For much of this time, 403 was geographically one of the largest NPAs in North America. On October 21, 1997, area code 867 was formed out of the territories' portion of 403 and the portion of area code 819 located in the Northwest Territories.

By early 1997, area code 403 was threatened by exhaustion because of the rapid growth of telecommunication services demand for pagers, cellphones, and computer modems, as well as growing competition among providers.[3] By September of 1997, Telus Communications and the Canadian Radio and Television Commission initiated relief actions in planning a north/south split of the 403 numbering plan area, with a boundary line drawn north of Red Deer and Stettler. The split became effective on January 25, 1999, so that the northern part, including Edmonton, received the new area code 780.[4] Permissive dialing of 403 for calls terminating in the new 780 numbering plan area continued across the province until July 12, 1999.

Within a decade, area code 403 was close to exhaustion once again. The projected exhaust date was March 2009.[5] The solution for mitigation was to implement area code 587 as a province-wide overlay for both numbering plan areas of the province.[6][7][8] Optional ten-digit dialing began on June 23, 2008 and became mandatory on September 12, 2008.[9] On September 20, 2008, Telus Mobility began to assign 587 telephone numbers to new customers in Calgary and Edmonton.

On April 9, 2016, all three numbering plan areas of the province were overlaid with an additional area code, 825.[10]

On January 21, 2022, the province was once again overlaid with another area code, 368.[11][12]

Local exchange carriers

[edit]

The incumbent local exchange carrier (ILEC) in 403 is Telus. Prior to 1997, the larger 403 included EdTel (Edmonton Telephones, now part of Telus) and Northwestel as ILECs. Before 1990, Telus was known as Alberta Government Telephones and was a provincial government department.[13]

Service area and central office codes

[edit]
  • Acadia Valley (403)-972
  • Acme (403)-546
  • Airdrie (403)-316 420 768 912 945 948 960 980
  • Alix (403)-747
  • Arrowwood (403)-534
  • Banff (403)-431 497 760 762 763 778 951 985 996
  • Barons (403)-757
  • Beiseker (403)-947
  • Big Valley (403)-876
  • Blackfalds (403)-600 885
  • Bragg Creek (403)-949
  • Brocket (403)-965
  • Brooks (403)-362 363 376 409 427 501 633 793 794 925
  • Burdett (403)-833
  • Calgary (403)-200 201 202 203 204 205 206 207 208 209 210 212 213 214 215 216 217 218 219 220 221 225 226 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 303 305 312 313 319 333 338 351 354 355 365 366 367 369 370 371 374 375 383 384 385 386 387 389 390 397 398 399 400 401 402 404 407 408 410 428 437 440 441 444 450 451 452 453 454 455 456 457 461 462 463 464 465 466 467 470 471 472 473 474 475 476 477 478 479 481 483 487 500 503 508 509 510 512 513 514 515 516 517 519 520 521 523 530 531 532 535 536 537 538 539 540 541 542 543 547 554 560 561 567 568 569 570 571 585 589 590 592 604 605 606 607 608 612 613 614 615 616 617 618 619 620 629 630 640 645 648 650 651 656 660 661 662 663 667 668 669 670 671 680 681 685 686 689 690 691 692 693 695 696 697 698 699 700 701 702 703 705 708 710 714 716 717 718 719 720 723 724 726 727 730 731 735 736 744 747 750 764 765 766 767 769 770 771 774 775 776 777 781 796 797 798 799 800 801 802 803 804 805 806 807 808 809 813 815 816 817 818 819 826 827 828 829 830 831 835 836 837 850 852 860 861 862 863 869 870 873 874 875 879 880 888 889 890 891 899 906 909 910 918 919 920 921 922 923 926 927 931 943 944 955 956 966 968 969 970 971 973 974 975 978 984 987 988 990 991 992 993 997 998 999
  • Canmore (403)-493 609 621 675 678 679 688 707 812 953 961
  • Cardston (403)-653 659
  • Carstairs (403)-337 940
  • Castor (403)-882
  • Cereal (403)-326
  • Champion (403)-897
  • Claresholm (403)-468 489 490 625 682 706
  • Clive (403)-784
  • Coaldale (403)-345 405
  • Cochrane (403)-709 840 851 855 907 932 981
  • Cowley (403)-751
  • Cremona (403)-637
  • Coutts (403)-344
  • Crossfield (403)-941 946
  • Crowsnest Pass (403)-372 459 562 563 564 582 583 623 753
  • Delburne (403)-749
  • Diamond Valley (403)-933
  • Didsbury (403)-335 439 518
  • Donalda (403)-883
  • Drumheller (403)-321 334 436 494 820 821 823 856
  • East Coulee (403)-822
  • Eckville (403)-746
  • Elkwater (403)-893
  • Elnora (403)-773
  • Empress (403)-565
  • Exshaw (403)-673 674
  • Foremost (403)-867
  • Fort Macleod (403)-553
  • Glenwood (403)-626
  • Halkirk (403)-884
  • Hanna (403)-857
  • High River (403)-336 422 469 498 601 602 603 649 652 841 908
  • Hilda (403)-838
  • Hill Spring -See Glenwood
  • Hussar (403)-787
  • Innisfail (403)-227
  • Irricana (403)-935
  • Irvine (403)-834
  • Jenner (403)-898
  • Kananaskis Improvement District (403)-591
  • Lacombe (403)-782 786 789
  • Lake Louise (403)-434 522
  • Langdon (403)-936 954
  • Leslieville (403)-729
  • Lethbridge (403)-308 315 317 320 327 328 329 330 331 332 353 359 360 380 381 382 388 393 394 524 593 634 635 694 715 795 849 892 894 915 929 942
  • Lomond (403)-792
  • Longview (403)-558
  • Magrath (403)-758 759
  • Manyberries (403)-868
  • Medicine Hat (403)-458 487 488 502 504 525 526 527 528 529 548 580 581 594 712 866 878 905 926 928 952 957 977 979
  • Milk River (403)-647
  • Milo (403)-599
  • Mirror (403)-788
  • Morley (403)-881
  • Nobleford (403)-824
  • Okotoks (403)-306 842 917 938 939 982 995
  • Olds (403)-415 438 507 556 559 586 672 791 994
  • Penhold (403)-886
  • Picture Butte (403)-732
  • Pincher Creek (403)-339 432 484 624 627 632 683
  • Ponoka (403)-704 783 785 790 913 963
  • Raymond (403)-752
  • Red Deer (403)-302 304 307 309 314 318 340 341 342 343 346 347 348 349 350 352 356 357 358 373 391 392 396 406 505 506 550 588 596 597 598 713 754 755 848 872 877 896 967 986
  • Rimbey (403)-843
  • Rocky Mountain House (403)-322 418 429 844 845 846 847 871 895
  • Rolling Hills (403)-964
  • Schuler (403)-839
  • Seven Persons (403)-832
  • Stettler (403)-323 430 740 741 742 743 916
  • Stirling (403)-756
  • Strathmore (403)-324 325 361 480 499 814 901 902 934 962 983
  • Sunchild O'Chiese (403)-989
  • Sundre (403)-419 426 636 638
  • Sylvan Lake (403)-858 864 887
  • Taber (403)-223 416
  • Three Hills (403)-443 924
  • Trochu (403)-442 914
  • Turner Valley (403)-933
  • Vauxhall (403)-654
  • Vulcan (403)-485 486 496
  • Walsh (403)-937
  • Warner (403)-642
  • Waterton Park (403)-859
  • Youngstown (403)-779

See also

[edit]
[edit]

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Area code 403

View on Grokipedia
from Grokipedia
Area code 403 is a telephone area code in the North American Numbering Plan (NANP) serving the southern portion of Alberta, Canada, encompassing major urban centers such as Calgary, Red Deer, and Lethbridge, along with surrounding rural communities.[1][2] It operates within the Mountain Time Zone (MST/MDT) and currently overlaps with area codes 587, 825, and 368 in its serving territory.[1] Established on January 1, 1947, as one of Canada's original nine NANP area codes, 403 initially covered the entire province of Alberta and later extended to the Yukon Territory and parts of the Northwest Territories.[3][4] The history of area code 403 reflects the rapid population and economic growth in Alberta, particularly driven by the oil and gas industry in the south. In October 1997, the Yukon and Northwest Territories were separated to form area code 867, restoring 403's focus to Alberta alone.[3] A significant split occurred on January 25, 1999, when northern Alberta, including Edmonton, received the new area code 780, allowing 403 to be retained for the southern region centered on Calgary.[3][5] To address numbering exhaustion amid continued demand, overlay area code 587 was introduced on September 19, 2008, initially planned for the entire province but effectively serving both 403 and 780 territories without requiring customers to change numbers.[3] This was followed by 825 on April 9, 2016, and 368 on April 23, 2022, creating a total of five area codes (403, 587, 825, 368, and 780) across Alberta to ensure long-term capacity.[3][6] Today, area code 403 supports a diverse economy in southern Alberta, from urban hubs like Calgary—the province's largest city and economic powerhouse—to agricultural and tourism areas in the Rocky Mountains and prairies.[2] It serves approximately 248 cities and towns, utilizing 781 telephone prefixes, and remains a key identifier for the region's telecommunications infrastructure.[7] The overlays have enabled ten-digit dialing throughout the province since 2008, promoting efficient number resource management under the oversight of the Canadian Radio-television and Telecommunications Commission (CRTC).[8]

Overview

Geographic Coverage

Area code 403 serves the southern third of Alberta, Canada, extending from the Canada–United States border northward to the boundary with area code 780, which covers the northern two-thirds of the province. This territory includes 182 telephone exchanges spread across diverse landscapes in the southern portion of the province.[9] The coverage encompasses major population centers, with Calgary as the largest city and economic hub, having a population of approximately 1.6 million in 2025; other key cities include Red Deer, Lethbridge, and Medicine Hat, alongside numerous surrounding towns and rural communities such as Banff, High River, Airdrie, Okotoks, Brooks, and Drumheller.[9][10] Specific regions within this area include the arid Palliser's Triangle in the southeast, the rolling foothills west of Calgary, and the eastern slopes of the Rocky Mountains, supporting a mix of agricultural, industrial, and tourism-based economies.[7] As of 2025 estimates, area code 403 serves roughly 2.5 million people across approximately 200,000 square kilometers, representing about one-third of Alberta's total land area and a substantial share of its southern population. Area codes 587, 825, and 368 overlay this same geographic territory to accommodate growing demand for telephone numbers.[11][12]

Associated Overlays

Area code 403 is overlaid by area codes 587, 825, and 368, which provide additional numbering resources across the same geographic territory in southern Alberta, encompassing major urban centers like Calgary. These overlays were implemented to combat the exhaustion of available telephone numbers due to rapid population growth and increased demand for telecommunications services, particularly in high-growth regions, without requiring changes to existing local calling areas or rate boundaries. All overlay codes allow for the assignment of new telephone numbers within the identical service territory as 403, ensuring continuity for existing subscribers while expanding capacity.[11] The first overlay, area code 587, was introduced on September 19, 2008, as a distributed overlay covering both the 403 and 780 regions province-wide to address imminent number shortages. This addition marked the transition to mandatory 10-digit dialing for all local calls in Alberta, effective the same year, eliminating the need for seven-digit dialing and accommodating the multiple area codes. Subsequent overlays built on this framework: area code 825 entered service on April 9, 2016, further supplementing the numbering pool amid continued demand pressures.[13][14] Area code 368 was activated on April 23, 2022, as the latest distributed overlay for the 403/587/825 and 780/587/825 complexes, providing yet more central office codes to avert projected exhaustion. Unlike earlier implementations that included permissive dialing periods, the rollout of 368 enforced immediate mandatory 10-digit dialing with no transitional phase, aligning with the established province-wide practice since 2008. This measure was approved by the Canadian Radio-television and Telecommunications Commission (CRTC) to ensure sufficient resources without disrupting service.[15] The combined numbering pool for area codes 403, 587, 825, and 368 was projected in 2019 to meet demand until approximately 2030, based on utilization data and growth projections at that time. This extended capacity reflects the effectiveness of the overlay strategy in managing Alberta's telecommunications expansion.[11]

History

Establishment and Early Use

Area code 403 was established in 1947 as one of the original 86 codes in the North American Numbering Plan (NANP), developed by AT&T and the Bell System to standardize long-distance dialing across North America.[16] It was put into service in 1947, marking the introduction of structured area codes in Canada.[1] Initially, the code encompassed the entire province of Alberta, serving all regions from no prior dedicated numbering plan, as Alberta lacked its own telephone area code before the NANP's implementation.[1] This broad coverage included areas that would later be reassigned to codes such as 780 and various overlays due to population growth and demand.[1] In 1960, the coverage of area code 403 was extended northward to include the Yukon Territory and parts of the Northwest Territories as telephone interconnections developed.[3] However, on October 21, 1997, these northern areas were separated to form the new area code 867, restoring 403's focus exclusively to Alberta.[3] In its early years, the telephone infrastructure supporting area code 403 relied heavily on manual switchboards operated by human operators to connect calls, a system common across rural and urban Alberta at the time.[17] By the 1950s, Alberta Government Telephones began transitioning to automated dial systems in select communities, enabling customers to make local calls without operator assistance, though full direct distance dialing did not arrive until 1961 in places like Red Deer.[18] The code initially served a population of approximately 825,000 residents in Alberta, facilitating communication amid post-war expansion in agriculture, oil, and urban centers like Calgary.[19] Administration of area code 403 fell under Alberta Government Telephones (AGT) for provincial operations, with broader NANP oversight by AT&T and the Bell System in its formative years.[17] Regulatory authority for telecommunications, including numbering plans, shifted to the Canadian Radio-television and Telecommunications Commission (CRTC) in 1976, when the agency expanded its mandate to encompass telephone services beyond broadcasting.[20] This transition formalized federal oversight in Canada, ensuring coordinated management of area codes amid growing demand.

1999 Provincial Split

Area code 403 was originally established in 1947 to cover the entire province of Alberta. By the late 1990s, however, the rapid population growth in Edmonton and northern Alberta led to projected exhaustion of available telephone numbers under the single area code, prompting relief planning to begin as early as 1994.[3][21] The split took effect on January 25, 1999, dividing the province along an east-west boundary north of Red Deer, with area code 780 assigned to northern Alberta—including Edmonton and extending to the Northwest Territories border—while 403 was retained for the southern region centered on Calgary.[22] This geographic division aimed to allocate numbering resources more efficiently amid the province's booming demand for telecommunications services. The transition minimized disruption through a permissive dialing period, allowing 7-digit local calls within the new 780 area until July 12, 1999, after which 10-digit dialing became mandatory for calls crossing the boundary; 10-digit dialing for long-distance calls was required immediately upon implementation. Existing telephone numbers were grandfathered, ensuring no changes for customers in either area and resulting in negligible impact on users. The split successfully extended the usable life of area code 403 by approximately 10 years and provided dedicated numbering for northern Alberta's initial population of about 1 million residents.[23][24]

Subsequent Overlays

Following the 1999 split that created area code 780 for northern Alberta and provided partial relief to the southern region, subsequent overlays were introduced to address ongoing numbering shortages driven by population growth and increased demand for telephone numbers.[14] The first post-split overlay, area code 587, was approved by the Canadian Radio-television and Telecommunications Commission (CRTC) in Telecom Decision CRTC 2007-42 to serve the entire province as a distributed overlay for both 403 and 780 regions. It entered service on September 19, 2008, initially on a permissive basis allowing seven-digit dialing, but mandatory ten-digit dialing was implemented province-wide on that date to accommodate rapid growth, particularly in Calgary and surrounding areas.[25] This addition extended the usable life of the existing codes amid projections of exhaustion for 403 by early 2009. By 2013, forecasts indicated that the 403/587/780 complex would exhaust central office codes by mid-2016 due to sustained demand from economic expansion and mobile services. In response, the CRTC approved area code 825 in Telecom Decision CRTC 2013-574, establishing it as a province-wide distributed overlay. The code was activated on April 9, 2016, with immediate mandatory ten-digit dialing for all local calls across Alberta to ensure seamless integration and prevent disruptions.[14] Continued population booms following the 2016 overlay led to renewed projections of exhaustion by March 2022 for the 403/587/780/825 cluster.[11] The CRTC approved area code 368 in Telecom Decision CRTC 2019-130 as a fourth distributed overlay covering all 337 exchanges in Alberta, recommended by the relief planning committee to support approximately 3 million active telephone lines.[11] Although initially scheduled for May 2021, implementation was delayed and the code launched on April 23, 2022, requiring ten-digit dialing from the outset.[26] These overlays—587, 825, and 368—have been coordinated by the Canadian Numbering Administration Consortium (CNAC) under CRTC oversight through the Canadian Steering Committee on Numbering (CSCN), ensuring equitable distribution without geographic splits.[26] As of 2025, no additional relief measures are planned for the Alberta area code complex, with current forecasts indicating sufficient capacity through at least the late 2020s.[27]

Service Providers

Incumbent Carriers

The primary incumbent local exchange carrier (ILEC) for area code 403 is TELUS Communications Inc., which serves as the main provider of wireline telephone services in southern Alberta.[28] TELUS assumed this role following the 1990 privatization of Alberta Government Telephones (AGT), a provincial Crown corporation that had operated as the incumbent from 1908 until its restructuring.[29] AGT was established to provide telephone services across Alberta, initially focusing on connecting rural and urban areas under government oversight.[30] As the ILEC, TELUS maintains the central offices that form the backbone of the landline network in the 403 region, ensuring reliable connectivity for voice services.[31] It also handles the initial assignment of telephone numbers within its operating territory, coordinating with the Canadian Numbering Administrator to allocate resources efficiently.[31] Additionally, TELUS complies with Canadian Radio-television and Telecommunications Commission (CRTC) regulations on unbundling, which require it to provide competitors access to its network elements, such as loops and switching facilities, to promote competition in local services.[31] TELUS's coverage under area code 403 is extensive, particularly dominating urban centers like Calgary and Lethbridge, where it supports the majority of residential and business landlines.[28] In rural areas of southern Alberta, TELUS continues to operate as the primary ILEC, though some limited services may overlap with historical providers prior to full integration in the 1990s.[29] This infrastructure role remains critical despite the rise of overlays like 587 and 825, which do not alter TELUS's core responsibilities for number assignment and maintenance.

Competitive and Wireless Providers

Following the Canadian Radio-television and Telecommunications Commission (CRTC) deregulation of local telecommunications markets in 1997 and 1998, competitive local exchange carriers (CLECs) began offering voice services in competition with incumbents across Alberta, including the 403 area code region.[32][33] Providers such as Shaw Communications (acquired by Rogers in 2023), Distributel, and TekSavvy entered the market by reselling incumbent facilities or providing voice over Internet Protocol (VoIP) services bundled with broadband. These CLECs focus on urban centers like Calgary and Edmonton, offering cost-effective alternatives to traditional landlines through digital delivery over high-speed Internet connections.[34] Wireless carriers serving the 403 area code and its overlays (587, 825, and 368) include major national operators Rogers Wireless, Bell Mobility, and TELUS Mobility, which assign mobile numbers from these codes to subscribers in southern Alberta.[35] These providers leverage extensive 4G LTE and 5G networks to deliver voice, text, and data services, with coverage encompassing both urban and rural areas within the region.[36] Mobile virtual network operators (MVNOs), such as Public Mobile, operate on these underlying networks—primarily TELUS for Public Mobile—without owning infrastructure, enabling lower-cost plans while utilizing the same numbering resources.[37] As of 2023, mobile services accounted for 55.2% of total telecommunications revenues in Canada, reflecting high adoption in Alberta where wireless subscriptions surpass population levels.[38] As of 2024, mobile revenues increased to 56.4% nationally, with continued growth in Alberta amid a provincial population exceeding 5 million.[39] CLECs have gained presence in the market for voice services integrated with broadband, particularly through bundled VoIP offerings in urban areas. As of 2024, large incumbents hold 56.4% of overall telecom revenues, indicating competitive dynamics in IP-based solutions.[38] Wireless penetration in the region exceeds 90% of the population as of 2023, supported by regulatory mandates for local number portability implemented since 1997, which allows seamless switching between wireline and wireless providers while retaining 403-series numbers.[32][40] This portability, managed through the Canadian Local Number Portability Consortium, has facilitated competition by reducing barriers to entry for both CLECs and wireless operators.[41]

Technical Specifications

Central Office Prefixes

The central office prefixes, or NXX codes, for area code 403 span the range 200–999, excluding reserved blocks for services such as 211 (community information), 311 (non-emergency municipal services), 411 (directory assistance), and 911 (emergency). These codes identify specific exchanges or rate centers within the southern Alberta region. As of November 2025, utilization stands at approximately 781 active NXX assignments out of roughly 800 available (excluding reservations), representing about 98% exhaustion in some pools, prompting ongoing allocations by the Canadian Numbering Administrator (CNAC) to incumbent and competitive carriers based on demand forecasts and pooling requirements.[7][42] Major exchanges are concentrated in key urban centers, with Calgary holding the majority of assignments due to its population density. Other significant exchanges include Red Deer, Lethbridge, and Medicine Hat, each served primarily by TELUS Communications Inc. as the incumbent local exchange carrier (ILEC), alongside wireless and competitive providers sharing pooled codes. The NXX pools are shared with overlay area codes 368, 587, and 825 to support expanded numbering capacity without geographic splits.[43][44][45][46]
CityActive NXX Examples/RangesApproximate Number of PrefixesPrimary Serving Carriers
Calgary200–210, 225–229, 230–239, 240–259, 260–279, 280–289, 290–299, 300–301, 303, 305, 312–313, 319, 333, 338, 351, 354–355, 365–371, 374–375, 383–387, 389–390, 397–399, 400–402, 404, 407–408, 410, 428, 437, 440–441, 444, 450–479, 481, 483, 500, 503, 508–509, 510, 512–521, 523, 530–543, 547, 554, 560–561, 567–571, 585, 589–590, 592, 604–608, 612–620, 629–630, 640, 645, 648, 650–651, 656, 660–663, 667–671, 680–681, 685–686, 689–699, 700–703, 705, 708, 710, 714, 716–720, 723–724, 726–727, 730–731, 735–736, 744, 750, 764–771, 774–779, 781, 796–799, 800–809, 813, 815–819, 826–831, 835–837, 850, 852, 860–863, 869–870, 873–875, 879–880, 888–891, 899–900, 903, 906, 909–910, 918–920, 921–923, 926–927, 930–931, 943–944, 955–956, 966, 968–975, 978, 984, 987–988, 990–993, 997–999314TELUS Communications Inc. (OCN 8084), TELUS Mobility (OCN 8301), various CLECs and wireless providers via pooling[43]
Red Deer302, 304, 307, 309, 314, 318, 340–343, 346–352, 356–358, 373, 391–392, 396, 406, 505–506, 550, 588, 596–598, 713, 754–755, 848, 872, 877, 896, 967, 98638TELUS Communications Inc. (OCN 8084), TELUS Mobility (OCN 8301)[44]
Lethbridge308, 315, 317, 320, 327–332, 353, 359–360, 380–382, 388, 393–394, 524, 593, 634–635, 694, 715, 795, 849, 892, 894, 915, 929, 94232TELUS Communications Inc. (OCN 8084), TELUS Mobility (OCN 8301), Bell Mobility (OCN 6574)[45]
Medicine Hat458, 487–488, 502, 504–529, 548, 580–581, 594, 712, 866, 878, 905, 928, 952, 957, 977, 97924TELUS Communications Inc. (OCN 8084), TELUS Mobility (OCN 8301), Bell Mobility (OCN 6574)[46]

Numbering Plan Boundaries

The numbering plan boundaries for area code 403 are defined under the regulatory framework of the North American Numbering Plan Administrator (NANPA) and the Canadian Radio-television and Telecommunications Commission (CRTC), which oversee the assignment and relief of numbering plan areas (NPAs) in Canada per the Telecommunications Act.[21] These boundaries generally follow municipal and exchange lines to ensure technical compliance, though some rate center overlaps exist to accommodate local calling areas.[21] Geographically, area code 403 encompasses the southern portion of Alberta, with its northern boundary established by a horizontal line north of Red Deer and Stettler along approximately the Red Deer-Yellowhead Highway corridor, resulting from the 1999 provincial split with area code 780.[47] The eastern boundary aligns with the Saskatchewan provincial border, the western with the British Columbia border, and the southern with the Montana, United States, border, covering 142 rate centers or exchanges in this region.[21] Exceptions include certain rural exchanges shared with area code 780 prior to the 1999 split, which permit seven-digit dialing in inter-NPA local calling areas to avoid central office code conflicts.[21] Overlay area codes such as 587, 825, and 368 share identical geographic boundaries with 403, implemented as distributed overlays across the same southern Alberta territory to provide numbering relief without altering the underlying plan boundaries.[11] No boundary changes are currently planned for area code 403, though the CRTC and NANPA continue to monitor demand influenced by urban sprawl in areas like Calgary's exurban regions to ensure long-term sustainability.[48] Central office prefixes are allocated strictly within these defined boundaries to maintain compliance.[21]

References

  1. 403 Area Code - Location map, time zone, and phone lookup
  2. 403 Area Code – Get a Calgary, AB Local Phone Number - Phone2
  3. [PDF] Canadian Geographic Area Code Relief History
  4. Canadian Area Codes
  5. Albertans getting new digits with introduction of new area code in April
  6. Alberta getting new area code 368 in 2022 - CTV News
  7. 403 Area Code: Complete Location Info, Time Zone
  8. [PDF] Telecom Notice of Consultation CRTC 2012-656
  9. ARCHIVED - Telecom Decision CRTC 2007-42
  10. Calgary Population 2025
  11. Telecom Decision CRTC 2019-130
  12. Population estimates, quarterly - Statistique Canada
  13. 587 Area Code - Location map, time zone, and phone lookup
  14. CRTC to Introduce a New Area Code in Alberta in 2016 - Canada.ca
  15. Telecom Decision CRTC 2021-101
  16. United States Phone Numbers: Format, Area Code & Validation Guide
  17. Direct Distance Dialling Arrives in Western Canada - discoverAPEGA
  18. History of local telephone service - Red Deer Express
  19. [XLS] Alberta Population 1921-Current
  20. Bell Canada (and other Canadian telecommunications companies)
  21. CRTC 50th anniversary
  22. [PDF] NUMBERING RELIEF
  23. [PDF] Planning Document NPA 403/780 Numbering Relief
  24. [PDF] NPA 780 - Canadian Numbering Administrator
  25. [PDF] 1999 official population list - Open Government program
  26. [PDF] - 1 - NPA 403 Commission Directives On October 7, 2004, the ...
  27. Welcome to the Canadian Numbering Administrator Site
  28. [PDF] April 2025 North American Numbering Plan (NANP) Exhaust Analysis
  29. TELUS Corporation - SEC.gov
  30. Telephones | The Canadian Encyclopedia
  31. TELUS | Encyclopedia of the Great Plains
  32. Responsibilities and Regulatory Obligations - CRTC
  33. https://crtc.gc.ca/eng/archive/1997/dt97-8.htm
  34. ARCHIVED - Telecom Decision CRTC 98-8
  35. TekSavvy: Fair Priced Internet, Phone, TV in Canada
  36. Southern Alberta (403) Telephone Exchanges / Prefixes - wetmore.ca
  37. Best Cell Phone Coverage in Alberta | WhistleOut
  38. Which Network Is Behind Your MVNO? - WhistleOut
  39. Canadian Telecommunications Market Report 2025 - CRTC
  40. [PDF] Dynamic Competition in Telecommunications - C.D. Howe Institute
  41. ARCHIVED - Telecom Order CRTC 97-1243
  42. About - CLNPC
  43. CO Code Status - CNA - Canadian Numbering Administrator
  44. Local calling guide: Rate centre information
  45. Rate centre information - Local calling guide
  46. Rate centre information - Local calling guide
  47. Local calling guide: Rate centre information
  48. [PDF] New Area Code for the 403 Area - TELUS
  49. [PDF] Revision to relief implementation schedule for area codes 403, - CRTC
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