is a Japanese professional cyclist, who currently rides for UCI Continental team .
Career
After three years at Japanese UCI Continental team , Oka signed with French UCI ProTeam in 2020, joining compatriots Fumiyuki Beppu, Masahiro Ishigami, and Hideto Nakane. Oka made his debut for the team at the 2020 La Tropicale Amissa Bongo.
At the end of the 2020 season, it was reported that Oka was one of several riders who filed complaints to the UCI about team manager Philippe Lannes trying to force them out of the team midway through their contracts and evict them out of the team house, amidst controversies over "missing payments, contracts not being honored, and threatening behavior" towards the riders' futures on the team. Speculation arose that Lannes' actions, especially towards Oka and Ishigami, partially stemmed from his frustrations over Japanese sponsor Nippo leaving the team, further contributing to the team's financial troubles; however, both riders remained registered with team for the 2021 season.
On 28 April 2021, Oka received a four-month suspension from the UCI after an anti-doping control test came back positive for acetazolamide, a drug banned by WADA that is often used to treat altitude sickness. Given the retroactive suspension from the date of the positive on 13 December 2020, Oka was eligible to race again on 24 May 2021.
On 29 June, Oka signed with , joining teammate Masahiro Ishigami, who had signed a month earlier.
Personal life
Oka's older brother Yasumasa is also a professional cyclist.