The 1:00 p.m. voyage from Swartz Bay to Tsawwassen and the 3 pm trip from Tsawwassen to Swartz Bay were both canceled after Spirit of British Columbia suffered a mechanical issue with a hydraulic ram.
The failure is preventing the doors of the ferry from closing, a statement from BC Ferries said.
The breakdown came on a busy travel day for the service as ferry travelers were returning home following the Family Day long weekend.
By Tuesday afternoon, all voyages between Swartz Bay and Tsawwassen were fully booked through the remainder of the day as well as into Wednesday morning.
BC Ferries said it was working to resolve the mechanical issue. The company apologized for the inconvenience.
The ferry operator said customers with bookings would have their bookings canceled and reservation fees refunded. Travel would revert to a standby basis.