Tanaka's first major international competition was the 2009 World Championships, where he qualified 10th to the individual all-around with a score of 86.650.

[3] Tanaka competed for the Japanese team which won the silver medal in the team-all around competition at the 2010 World Championships, contributing scores of 14.166 on still rings, 15.483 on parallel bars, and 14.433 on high bar.

[7] In the individual all-around, Tanaka was in the silver medal position going into the final rotation, when a mistake on the pommel horse dropped him to sixth.

His overall score was 89.407, a major improvement from his performance in qualification, and just over a point away from medalling.

[8] In the parallel bars final, he once again just missed out on a medal, placing fourth with a score of 15.500.