Jim Nill, general manager of Canada's national men's team, made the announcement on Monday — two days after Hamuis and his Canucks were eliminated from the NHL post-season.
Hamhuis, from Smithers, B.C., will represent Canada for the ninth time in international competition. He most recently helped his country win a gold medal at the 2014 Olympic Winter Games in Sochi, Russia.
The 32-year-old blue-liner has played in the IIHF world championship on five previous occasions (2006, 2007, 2008, 2009, 2013), winning a gold medal in 2007 and silver in 2008 and 2009.
Canada opens the tournament against Latvia on May 1. It will also face Austria, the Czech Republic, France, Germany, Sweden and Switzerland in preliminary-round play.
With the addition of Hamhuis, Canada's roster now stands at 22 players — two goaltenders, six defenceman and 14 forwards.