The versatility and effectiveness of a maritime version of the Harrier were clear as early as 1966, but it was not until May 1975 that the go-ahead was given for development of a dedicated naval variant. Compared to the RAF's Harrier GR.Mk 3, this introduced a new forward fuselage seating the pilot higher to provide space for extra avionics which included a Blue Fox multi-mode radar. The type was intended to be multi-role, and gained the designation FRS for fighter/reconnaissance/strike (for which latter role it carried a lightweight version of the free-fall WE177 weapon).
The first of an initial batch of 24 Sea Harrier FRS.Mk 1s for the Royal Navy flew on 20 August 1978. Subsequently, a further 10 were ordered, followed by 14 in July 1982 (seven of the latter replacing attrition in FAA service, including the Falklands war) and a further nine in 1984. The Indian navy was the sole export customer, ordering 23 Sea Harrier FRS.Mk 51s.
The Sea Harrier proved of vital importance in the conflict to regain the Falklands Islands in 1982, scoring 22 confirmed victories for no losses during air combat. The shortcomings of the Sea Harrier highlighted by the conflict led to an ambitious mid-life upgrade. On 19 September 1988, BAe flew the first prototype conversion of the Sea Harrier FRS.Mk 2 (later F/A.Mk 2 and now designated Fa.Mk 2). This features a multi-function CRT cockpit with hands on throttle and stick controls, increased weapons and stores capability, Pegasus Mk 106 powerplant (based on the Mn 105 of the AV-8B), and most importantly, a Blue Vixen radar in a re-contoured radome. The radar allows compatibility with the AMRAAM missile for beyond visual range engagements. On 24 December 1998, the last of 18 new-build FA.Mk 2s was delivered, this adding to the total of 31 machines produced by conversion from FRS.Mk 1 standard. Both Sea Harrier variants saw extensive combat over Bosnia in 1996.
The Sea Harrier FA.Mk 2 was withdrawn from the Royal Navy in 2006 and replaced by the Harrier II.