At the 2008 Summer Olympics, Soni won a silver medal in the 100-meter breaststroke, finishing behind world record holder Leisel Jones of Australia 1:06.73 to 1:05.17. In the 200-meter breaststroke, Soni upset the heavily favored Jones, winning the gold medal and breaking Jones's world record with a time of 2:20.22. Jones finished second with a time of 2:22.05. After the race, Soni said, "It's been a long road to get here, I can't believe what just happened." Soni then combined with Natalie Coughlin, Christine Magnuson, and Dara Torres in the 4×100-meter medley relay to finish second behind Australia. Soni had the second best split time in the field (1:05.95) behind Jones (1:04.58).