The Sikorsky SH-3 Sea King was one among a family of very successful military helicopters which began life as an anti-submarine platform for the US Navy. The Sea King was unique in having a boat-like hull which actually permitted it to remain afloat in case of an emergency as well as remarkable performance figures: it was the first helicopter to exceed 200 mph in flight and also held the longest non-stop distance record (from offshore carriers in San Diego to Jacksonville). It's primary mission was anti-submarine warfare and thus was equipped with dipping sonar systems, sonobuoys, and a magnetic anomaly detector (MAD) in addition to carrying torpedoes or anti-ship missiles. The Sea King has been largely replaced by the SH-60 for ASW duties but is still used extensively in other support roles, search and rescue (SAR) and as the presidential transport, Marine One. Over 20 countries have used the Sea King including license production by Westland (UK), Agusta (Italy) and Mitsubishi (Japan).

Developed from the Sikorsky S-61, the Sea King prototype HSS-1 made its first flight on 11 March 1959 and was first ordered as the HSS-2, a name which was subsequently changed into the SH-3A. A number of improvements led to the SH-3D and, ultimately, the definitive SH-3H with advanced sensors and equipment which was used extensively during the Gulf War. Other versions of the Sea King include the RH-3A minesweeper which had a strengthened fuselage for towing operations, the UH-3H for logistic support and SAR missions, and the VH-3D VIP transports, better known as Marine One. Non-naval versions include the CH-3 long-range transport and the HH-3E SAR helicopter for the USAF (the HH-3F performs a similar duty for the USCG). Lastly, Canadian versions are known as the CH-124 while UK and Italian (AS-61) versions are described separately.