Motohashi was a member of Team Aomori which represented Japan at two Winter Olympics (2006 and 2010).

She skipped the Japan team at the 2002 World Junior Curling Championships, finishing last.

On the World Curling Tour, Motohashi won the 2007 Meyers Norris Penny Charity Classic and the 2009 Twin Anchors Invitational while playing for Meguro, and later skipped her own rink to win the 2014 Avonair Cash Spiel.

Motohashi was part of the Japanese team that won the 2018 Olympics women curling bronze medal.

Holding Teacher's License for Junior High School - Grade 2 in Japan (health and physical training).