S-class ferries are roll-on/roll-off (RORO) ferries operated by BC Ferries in British Columbia, Canada. They are the largest ferries in the BC Ferries fleet. The class comprises two ships, Spirit of British Columbia and Spirit of Vancouver Island, which were completed in 1993 and 1994 respectively. They serve the ferry route between Tsawwassen and Swartz Bay. 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.

British Columbia Ferry Services Inc., operating as BC Ferries (BCF), is a former provincial Crown corporation, now operating as an independently managed, publicly owned Canadian company. BC Ferries provides all major passenger and vehicle ferry services for coastal and island communities in the Canadian province of British Columbia. Set up in 1960 to provide a similar service to that provided by the Black Ball Line and the Canadian Pacific Railway, which were affected by job action at the time, BC Ferries has become the largest passenger ferry line in North America, operating a fleet of 41 vessels with a total passenger and crew capacity of over 27,000, serving 47 locations on the B.C. coast.