In 2017, the class underwent conversion to a dual-fuel propulsion system that would allow them to use either marine diesel fuel or liquefied natural gas.

[4][5] The vessels were initially powered by four MAN 6L40/54[6] diesel engines driving two shafts creating 21,394 horsepower (15,954 kW).

[7] Further changes include navigation and propulsion equipment, steering and evacuation systems, lighting and air conditioning.

[3][12] On September 14, 2000, Spirit of Vancouver Island collided with the 9.72-metre (31.9 ft) Star Ruby while attempting to overtake the vessel in a narrow channel.

[9] Spirit of British Columbia was the first to undergo the conversion at the Remontowa Ship Repair Yard in Gdańsk, Poland, between 2017 and 2018.

Spirit of Vancouver Island's retrofit began in September 2018 and the vessel returned to service in April 2019.