Suenaga competed in a breaststroke double at the 2008 Summer Olympics in Beijing. Leading up to the Games, he cleared FINA A-standard entry times of 1:00.72 (100 m breaststroke) and 2:10.17 (200 m breaststroke) at the Olympic Trials in Tokyo. In the 100 m breaststroke, Suenaga posted a thirteenth fastest time of 1:00.67 on the first day of preliminaries to secure his spot for the semifinals. Followed by the next morning's session, Suenaga failed to qualify for the final, as he finished his semifinal run by matching his time and placement from the heats. Four days later, 200 m breaststroke, Suenaga missed the semifinals by 0.11 of a second, as he shared his seventeenth-place tie with Norway's Alexander Dale Oen in 2:11.30.