He has previously played in Nippon Professional Baseball (NPB) for the Tohoku Rakuten Golden Eagles and Yokohama DeNA BayStars.

[1] Hamaya spent the majority of the 2014 season with the farm team, posting a 2.83 ERA in 12 games.

[3] Hamaya spent the majority of the year with Yokohama's farm team, and struggled to a 32.40 ERA in 2 games with the main club.

[4] On February 8, 2021, Hamaya signed with the Ibaraki Astro Planets of the Baseball Challenge League.

[5] On July 19, 2021, Hamaya’s contract was purchased by El Águila de Veracruz of the Mexican League.