David Thomas, 50, and his 18-year-old son Stephen, from Swindon, Wiltshire, were among five Britons who died after the boat overturned near Vancouver Island on Sunday.
Nigel Hooker, 63, from Southampton, and ex-pats Jack Slater, 76, and Katie Taylor, 29, were also killed.
Stephen’s mother Julie was rescued from the stricken vessel, Leviathan II, along with 20 other people on board. A 27-year-old man from Sydney remains missing, while his girlfriend’s father is reportedly among the dead.
The Down’s Syndrome Association paid tribute to Stephen, whom it described as “very talented young man” and a “gifted photographer”, while his father was a “huge supporter” of the charity.
Microsoft said that it was “shocked and saddened” by the deaths of Mr Thomas, who worked for the company, and his son.
Mr Slater, who was originally from Salford but had lived in Canada for many years, was onboard the boat with his wife Marjorie but she was rescued, the BBC reported.
One of his daughters described her father’s death as a “tragedy beyond belief”.
The stricken boat, run by local tour firm Jamie’s Whaling Station, got into difficulty 13km from the small town of Tofino, around 241km west of Vancouver.
The company’s owner, Jamie Bray, said people were “traumatised” and in “disbelief” at what had happened.
Following the incident, Mr Bray said passengers on the boat were not required to wear life jackets.
“On larger vessels we’re not required to have the passengers wear the life jackets. On smaller open boats they are,” he said.
The company suffered a previous fatal accident, with a boat becoming swamped and rolling to an angle in 1998, killing the captain and a tourist, and an incident two years earlier when a captain suffered head injuries, but survived, after falling asleep and running a boat aground.