The Agusta AS-61 was one among a family of very successful military helicopters which began life as the Sikorsky Sea King anti-submarine platform for the US Navy and later license produced in Italy. 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. Italian AS-61s featured a strengthened airframe, revised horizontal tail, an uprated powerplant, and could be equipped with a wide variety of local and foreign armament such as Exocet or Harpoon missiles. Among the numerous export customers were Argentina, Brazil, Iraq, Iran, Peru, and Saudi Arabia.

Developed from the Sikorsky S-61, the Sea King prototype HSS-1 made its first flight on 11 March 1959 and eventually captured the interest of Italian authorities which signed a license agreement resulting in the first Agusta-built unit in 1967, the ASH-3D which were generally similar to the US original except for the changes mentioned above. These were followed by the improved ASH-3H which could perform a number of additional support roles while other variants included the ASH-3D/TS VIP transports, the AS-61N1 Silver civil helicopter (with reduced capacity but greater range than the US version), and the HH-3F search and rescue (SAR) type similar to the one used by the USCG.