Transport in Kollam includes various modes of road, rail and water transportation in the city and its suburbs. State-owned Kerala State Road Transport Corporation buses, private buses, Indian Railways, state-owned Kerala State Water Transport Department boats & ferry, taxis and auto rickshaws are serving the city of Kollam. The city had a strong commercial reputation since the days of the Phoenicians and Romans. Ibn Battuta mentioned Kollam Port as one of the five Indian ports he had seen during the course of his twenty-four year travels.

Kollam is known as the Cashew capital of the world. 90% of India's export quality Cashew Kernels are prepared from Kollam. It is the largest processed cashew exporter in the world. It is the headquarters of the Kollam District. The city of Kollam is home to the largest number of Bullet owners in India. As per the survey done by Royal Enfield in 2009, more than 60,000 bullet owners are there in Kollam city and nearly a lakh across the district. The enfield dealers in the city sells an average of 850 units every month.

City of Kollam(Quilon) was known as the commercial capital of the Venad region (comprising Thiruvananthapuram and Kollam districts). Kollam Seaport (now known as Kollam Port) was founded by Mar Abo at Thangasseri in 825. Kollam's transportation have that much of historic background.

Kollam Airport was the first aerodrome in the present day state of Kerala. During the 1920s, there were no other civil aerodromes in the kingdoms of Cochin, Travancore and the Malabar District at the time of the British ruled Madras Presidency. The airport stopped its operations when an accident involving a training aircraft at the boundary of the aerodrome, resulted in the death of the pilot and the trainee.

Kollam was the first city in South Kerala that got a rail connectivity. The first idea of a rail link from Madras to Quilon, the trading capital of the erstwhile Travancore Kingdom was conceived in 1873. Kollam–Sengottai railway line is the second railway line to come to the present day state of Kerala, the first in the native kingdom of Travancore. After a survey in 1888, work started in 1900 and was completed by 1902. The first goods train travelled on this route in 1902, while the first passenger train began its run in 1904. Before the arrival of rail networks in Trivandrum, Kings of old Travancore had used Kollam Junction railway station and Kollam Airport for their transportation needs. Kollam was the former capital of Venad Kingdom. The Madras-Quilon line was extended to the capital of the Princely State of Travancore on 4 January 1918.

The city and metropolitan area are served by major arterial roads that run either in an east-west or north-south direction. The intra-city transportation is mainly carried out by private buses whereas the inter-city services are carried out by KSRTC. Kollam is one among the five KSRTC zones in Kerala. The private city bus services in Kollam were blue in colour. Now buses in Kollam follows newly introduced colour code system like rest of Kerala and hence city buses are green and other moffusil buses are blue. As per the reports, there are 681 buses plying through the roads in Kollam district. There is only one Regional Transport Office(RTO) in the city so far which is Kollam RTO(KL-02). But there are 6 Sub-Regional Transport Offices in the district of Kollam: Karunagappally (KL-23), Kottarakkara (KL-24), Punalur (KL-25), Kunnathur (KL-61), Chadayamangalam (KL-81), Pathanapuram (KL-82).

There are two major bus stations and one bus terminal in the city.

There is no dedicated Urban Metro Transport company or corporation for Kollam. KSRTC's urban transport wing KURTC does very few AC buses to Punalur, Trivandrum and Kochi. Other wise the scene is completely dominated by green coloured private buses. The system suffers badly due to poor condition of buses, lack of speed, adequate passenger amenities or information system, lack of new routes on by-routes, lack of route numbering and rude behaviour of staff. There was an attempt to bring in number system a decade back which went in vain due to poor implementation and lack of co-operation. There is also lack of proper waiting sheds for passengers in bus stops of Kollam.