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 container 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.