The pair was spotted heaving on the rigging on a ship called Pacific Grove while they spent time with young people who are part of a charity that uses sailing to help them find direction. They were also joined by young people who are a part of JACK.org, which works to end stigma towards mental health.
While Kate helped hoist the sail, the prince continued to work on the rigging and cheered after the sails were finally hoisted.
During their visit, the royal pair chatted to the young people about mental health and listened to their personal stories. Prince William said: "So many people's natural reaction is to close down, talking things through is crucial…we're very glad you're still here. You're very brave and you should be very proud that you've shared your story."
He added: "We all need to be a lot more open about all this stuff. The more we're talking about mental health, the more we're finding there are so many more services needed for people who are struggling."
The Duchess changed from her earlier chic Zara and H&M ensemble to a suitable sailing outfit, donning a casual khaki Troy jacket, black leggings and white Superga shoes.
The couple are enjoying their final day in Canada, and Kate spent time chatting about her son Prince George at the Cridge Centre. 20-year-old Zara Auld from Victoria said: "Kate asked me what I like to do and I told her cooking. She asked me what and I said Italian like pizza and pasta and she said George loves that."