She medaled silver at the 2020 Winter Youth Olympics individually and also as part of the Japanese ski jumping mixed team.

[2][3] At the 2017–18 FIS Nordic Combined Continental Cup, Miyazaki ranked second overall behind Russia's Stefaniya Nadymova, having placed first once,[4] second twice,[5][6] and third once[7] across four events.

[8] Miyazaki represented Japan at the 2020 Winter Youth Olympics, medaling silver in the individual normal hill/4 km event[9] and also medaling silver as part of the Japanese team in the mixed team ski jumping event.

[10] In the 2020 Nordic Junior World Ski Championships, Miyazaki placed eighth individually[3] but medaled bronze as part of the Japanese team in the mixed team event.

[11] Miyazaki placed tenth in the 2021 FIS Nordic World Ski Championships.