[10] In August 1985, the United States Coast Guard icebreaker USCGC Polar Sea transited the Northwest Passage from Greenland to Alaska without formal authorization from Canada.

While the evaluation of the shipyards' bids was underway, the government received unsolicited proposals from Dome Petroleum and Canadian Marine Drilling (Canmar), Atlantic Towing Limited and Cleaver & Walkingshaw, and the Canadian subsidiary of the Finnish shipbuilder Wärtsilä claiming that all three proponents could develop and deliver an Arctic Class 8 icebreaker that would meet all requirements at substantially lower cost and shorter delivery time than the original Polar 8 design developed by German & Milne.

[9][13][14] On 2 March 1987, the Canadian government signed a letter of intent for the construction of the Polar 8 to Versatile Pacific Shipyards (formerly Burrard-Yarrows) of North Vancouver, British Columbia.

[25] In October 2012, a 1:25 scale model of the polar icebreaker was being evaluated in at the National Research Council's Institute for Ocean Technology in St. John's[29] with additional testing taking place at Aker Arctic's ice laboratory in Finland.

[30] In May 2013, the Vancouver Sun reported that the polar icebreaker and the Royal Canadian Navy's new joint support ships faced a scheduling conflict and that the Harper government would have to choose which project had priority.

[41] On 6 May 2021, the Government of Canada announced that it would procure two polar icebreakers, one of which would be built by Seaspan Vancouver Shipyards and the other by Davie Shipbuilding, with the first vessel entering service in 2030.

[43] Design updates since have included changing the propulsion layout and substituting the extra high tensile steel that was previously identified as a potential major risk item.

[44][45] In December 2022, the Government of Canada awarded Seaspan the Construction Engineering (CE) and long lead items contracts for the first polar icebreaker.