He competed for 2 season, in 2006 he clinched runners up just lose out to the champion Adrian Sutil, while he managed to get 7th in Macau GP.

Then for 2008 Oshima also competed in the 2008 Formula 3 Euro Series with Manor Motorsports as a member of the Toyota Young Driver Program (TDP).

Oshima returns to Japan in 2009, and he stepped into GT500 with Team Kraft alongside his former GT300 Champion teammate Ishiura.

In 2019 Oshina alongside Kenta Yamashita won the title against the KeePer TOM'S of Ryo Hirakawa and Nick Cassidy.

After that he did not compete in the series for four seasons, except one-off appearance in 2015 as he replaces Kazuki Nakajima for one race.

Oshima comes back to the rebranded Super Formula, as he returned to his former Team LeMans to race for 3 seasons.