The man, who is from the Lower Mainland, was swimming with a woman from a five-metre boat when they ran into trouble, according to Capt. John Kelly with the Kelowna fire department.
"The gentleman became distressed. Apparently his shoulder became dislocated and he was unable to get back to the boat," said Kelly.
"The boat was kind of moving away from them with the current, and when the female tried to assist to get him back to the boat, she was unable to do that and she was getting pulled under as well."
The woman was rescued by a jet skier, but the 24-year-old man could not be found.
Kelly says the search, which continued overnight, is now considered a recovery effort.