About 100 fans chanted, sang and waved flags as delegates arrived for FIFA's annual gathering in Vancouver, days after the club said it had struggled to find a buyer committed to keeping the team in the city.
The Whitecaps said on Monday that "stadium economics, venue access and revenue limitations" had made a sale more difficult, adding that the search for new ownership had been underway for 16 months.
"I wanted to come down given the threat of the team possibly moving," said season ticket holder Derek Hawksworth, who joined the protest.
"It's a rich history with the Whitecaps in North America and I want to show support because I love the team, I love the sport. We want Vancouver to stay and not relocate.
"The history is here and we want to continue with that history moving forward and fill the trophy cabinet."
The club, founded in 1974, won the North American Soccer League title in 1979 and has a long history in Vancouver soccer. Last season, the Whitecaps reached both the MLS Cup final and the CONCACAF Champions Cup final.
Las Vegas and Phoenix are reportedly the top contenders to become the team's new home city if it relocates.
Vancouver Mayor Ken Sim on Tuesday called on the provincial government, which owns the team's present stadium, to come to a "bridge deal" with the Whitecaps to make the situation at BC Place viable while a new stadium is designed and built.
The team's lease at BC Place expires at the end of the year.
On the field, Vancouver have been among the strongest teams in MLS this season. The Whitecaps are second in the Western Conference with 24 points from nine matches, three points behind the San Jose Earthquakes.