Hundreds of people have signed up for the Vancouver Sun Run to show their support for Boston, pushing the number of runners to more than 47,000 people.
"There's something special about runners. It's a very tight-knit audience, a tight group and they stick together," said Sun Run organizer Jamie Pitblado.
$10 from every late entry fee will go to the families of the Boston victims, Pitblado said. He is urging runners to wear blue and yellow, the official colours of the Boston run.
Three people were killed and more than 180 others injured when twin bombs went off near the finish line at Monday's Boston Marathon.
Organizers in Vancouver reviewed their safety plan in the wake of the attack, but decided against making any changes to the finish line or increasing their liability insurance.
Runners and spectators will be subject to backpack checks, Pitblado said.
Several road closures will be in effect on Sunday, starting at 5 a.m. PT and ending at 1:30 p.m.