In March 2017, Mihara competed at the 2017 World Championships in Helsinki, Finland. Ranked fifteenth in the short program after doubling and falling on a planned triple flip, Mihara ranked fourth in the free skate and climbed to fifth overall. In April, she competed as part of Team Japan at the 2017 World Team Trophy. She achieved a personal best of 72.10 points in the short program and then scored a Japanese national record of 146.17 points in the free skate. She finished second behind Medvedeva and 0.83 ahead of compatriot Wakaba Higuchi while Team Japan won the gold medal.