The Victoria Joint Rescue Co-ordination Centre reported just after 4:30 p.m. Monday that a search operation was underway for a "man overboard" from the Queen of Oak Bay as it was south of Bowen Island.
Witness Don Genova said passengers on board the vessel saw the man go overboard, after which the ferry halted and a Zodiac was deployed.
Genova said witnesses believe the passenger who went overboard was in the water for at least 30 minutes.
Information about the passenger's condition has not been released.
Genova said a City of Vancouver police boat and a Canadian Coast Guard hovercraft arrived at the scene. The person pulled out of the water into one of the Zodiacs was then transferred to the Vancouver police boat.
"The police boat made a beeline for shore," said Genova. "An officer was performing CPR on whoever it was who was pulled out of the water."
Passengers on board the vessel had been asked by ferry crew to lend binoculars to rescuers and to look out windows to see if the passenger overboard could be spotted.
The Queen of Oak Bay travels between West Vancouver and Nanaimo eight times a day. All evening ferry crossings for the vessel were cancelled Monday.