Yuya Shirai is a Japanese mixed martial artist currently cmpeting in the welterweight division. Shirai has fought for DEEP, BAMMA, M-1 Global, Pancrase and DREAM.

Shirai comes from a Judo background and holds a black beltin the discipline. On June 8, 2003, he won the Japanese National Sambo Championship in the under 90 kilograms weight class.

Shirai became the DEEP Welterweight Champion, winning the title from Seichi Ikemoto at DEEP - 45 Impact, defeating Ikemoto via unanimous decision. Shirai's first title defense came against Shigetoshi Iwase at DEEP - 50 Impact, where he defeated Iwase by unanimous decision. He would go on to defend his title again at DEEP - 56 Impact, this time defeating Taisuke Okuno via unanimous decision. He put his title on the line again at Deep: 62 Impact against Deep newcomer Dan Hornbuckle. Shirai would lose his title to Hornbuckle by decision.