HMCS St. John's (FFH 340) is a Halifax-class frigate that has served in the Canadian Forces and the Royal Canadian Navy since her commissioning in 1996. She is the eleventh of twelve ships in her class which is based on the Canadian Patrol Frigate Project. St. John's is named after the city of St. John's, Newfoundland and Labrador, a port city associated with Canadian naval history and heritage, and is the first ship in the Royal Canadian Navy to bear the name.

St. John's serves on Canadian Armed Forces missions protecting Canada's sovereignty in the Atlantic Ocean and enforcing Canadian laws in its territorial sea and exclusive economic zone. St. John's has been deployed on missions throughout the Atlantic Ocean, to the Indian Ocean; specifically the Persian Gulfand Arabian Sea on anti-terrorism operations, to the north as far as Grise Fiordand to the Caribbean where she played a role in helping to stop the flow of illicit drugs to North America. She is assigned to Maritime Forces Atlantic (MARLANT) and her homeport is in Halifax, Nova Scotia.