HA(L)-3, (Helicopter Attack Squadron (Light) 3), nicknamed the "Seawolves", was a naval special operations aviation squadron unit in the United States Navy (USN) formed in support of United States Naval Special Warfare Command (USNSWC) operations and Mobile Riverine Forces (MRFs) during the Vietnam War.

Prior to the Vietnam War, the helicopter was a valued tool within the United States Army (USA) for aerial reconnaissance, airlift, medical evacuation (MEDEVAC) of wounded, and search and rescue (SAR). Helicopters within the USN were used for marine amphibious envelopment, search and rescue, vertical replenishment (VERTREP), and experimentally, as naval mine sweepers. As an offensive weapon, the Navy developed the helicopter as an anti-submarine warfare aircraft, developing the capability to carry and launch aerial torpedoes. As an offensive weapon for ground-based targets, the helicopter was relatively ignored in favor of traditional, fixed-wing aircraft.

In 1965, the US Navy began joint operations off the southern coast of South Vietnam in support of the growing war. In the same year, the Navy began limited Mobile Riverine Forces operations in the Mekong Delta, disrupting the Viet Cong's lines of communications, locating supply caches, and eliminating tax collecting stations. Based on the "Brown-water navy" Navy's early success, a commitment was made to continue river operations on a full-scale basis in the Mekong Delta. It was also determined that key to the survival of the boats operating in the rivers would be close air support (CAS).

Initially, the Brown-water Navy was supported by elements of the US Army's 145th Combat Aviation Battalion who had greater experience in helicopter gunship operations and tactics. Operating off a "Mothership", the USS Belle Grove, the Army and Navy worked together on Operation Jackstay. Although the joint effort was a success, it was felt that Naval aircrewman and Naval aviator would be more suitable for the mission, especially since the mission would require the pilots and crews to operate off the deck of ships in all weather conditions, day and night. This, coupled with Army's pilots and aircrews lack of training in shipboard operations, identified a need for a dedicated, United States Navy, helicopter gunship program in Vietnam.

In 1966, rotary wing support was originated as part of the response to the ongoing war in South Vietnam. Starting with Helicopter Combat Support Squadron ONE (HC-1), detachments of helicopter gunships transferred to the Navy to conduct combat operations in the Mekong Delta region of South Vietnam. HC-1 operated two-aircraft detachments of Army UH-1B gunships, staged from shore bases and patrol craft tenders. Providing a quick reaction, close air support (CAS) role for units of the Brown-water Navy, the effectiveness of the helicopter attack mission was quickly realized.

In response, the Navy began to widen the mission requirements. This created a need for a specific squadron in support of the mission requirements. In April 1967, HC-1 was divided into four separate units, Helicopter Sea Combat Squadron THREE (Navy Vertical Replenishment), Helicopter Combat Support Squadron Five, Helicopter Combat Support Squadron Seven (Navy Combat Search and Rescue), and Helicopter Attack Squadron (Light) 3, nicknamed the Seawolves.

In 1966, the Navy sent a message fleet-wide, asking for volunteer Naval Aviators to man HA(L)-3. From the response, eighty Aviators were chosen to be the first "Seawolves" and transferred to Vietnam. On 1 April 1967, HA(L)-3 was officially established in South Vietnam under the command of LCDR Joseph B. Howard.

The wolf on the patch was inspired by the lion logo on a Löwenbräu beer can; a trident as a symbol for the Navy was added, and a shield with a spade as a symbol for death with red and yellow colours as found on the flag of South Vietnam.