In 1977, the British Ministry of Defence issued a requirement for an anti-submarine warfare (ASW) helicopter to replace the Royal Navy's Westland Sea Kings.

Meanwhile, the Marina Militare (Italian Navy) was also seeking a replacement for its Agusta-built Sea Kings, leading Agusta to discussions with Westland about the possibility of a joint development.

When it became obvious that the Sea Kings were in need of immediate replacement, the EH101 was again part of a Canadian competition (Maritime Helicopter Project), against a variant of the Sikorsky H-92, for a total price tag of C$5 billion.

[2] The first operational CH-149 flight occurred in 2002 when a Cormorant of 442 Squadron performed a medical evacuation from a merchant ship 200 km (110 nmi) offshore in Hecate Strait.

An even more dramatic demonstration of Cormorant capabilities occurred in January 2003 when a 103 Squadron CH-149 successfully flew a 1,200 km round-trip rescue mission to the Finnish ro-ro cargo ship MS Camilla off Newfoundland.

The worldwide fleet of 190 AW101 helicopters had achieved in excess of 200,000 flight hours in Canada, UK, Italy, Denmark, Portugal, and Japan.

[8] On May 10, 2017, a report by the Senate Standing Committee on National Security and Defence recommended the government move forward with a proposal to expand the Cormorant fleet by upgrading the 14 CH-149 aircraft and converting 7 VH-71 airframes currently in storage to the same operational capability.