Hamelin, a 29-year-old native of Sainte-Julie, Que., won gold in the men's 500-metre event with a time of 40.803 seconds. He also picked up a silver in the 1,500m, finishing the race in 2:14.998.
Also earning spots on the 500-metre podium were Vladimir Grigorev of Russia (silver) and American Eduardo Alvarez, who took bronze.
South Korea's Noh Jinkyu skated to gold in the 1,500 with a time of 2:14.982 while Russia's Victor An earned bronze in the event.
Roberval, Que., native St-Gelais, 23, sprinted her way to a bronze in the women's 1,500-metre event, in a time of 43.715. China's Fan Kexin took gold and South Korea's Park Seung-Hi earned the silver medal.
Also on Saturday, 26-year-old Kamloops, B.C. native Jessica Hewitt just missed the podium in the women's 1,500m with a fifth place finish.
Hamelin, a two-time Olympic medallist, had a scare during the Canadian trials in Montreal last month. He was cruising through his events until a collision into the wall with two competitors during a men’s 1,000m semifinal stretched a ligament in his left ankle, but he appears ready to go as the season gets started.