The card will be headlined by a rematch between Yuki Egawa and Tatsuya Tsubakihara for the K-1 Featherweight title. The two previously fought at the K-1 World GP 2020 in Osaka, with Tsubakihara winning a majority decision. In the co-main event, the K-1 Super Lightweight champion Hideaki Yamazaki is scheduled to fight Fukashi Mizutani in a non-title bout. Former two-time Krush Welterweight title challenger Kaisei Kondo will face Maki Dwansonpong. K-1 and Krush Cruiserweight title challenger Hisaki Kato is scheduled to fight Mahmoud Sattari.

K-1 WORLD GP 2021 JAPAN Lightweight Title Match takes place on July 17, 2021, at Fukuoka Kokusai Center in Fukuoka, Japan. This kickboxing event features Gonnapar Weerasakreck defending his Lightweight title against Taio Asahisa in the main event. Other fighters include Kenta Hayashi, Koya Urabe, Rukiya Anpo, and Hikaru Hasumi across the card. A notable superfight pits Leona Pettas against Chihiro Nakajima.

The K-1 WORLD GP 2021 JAPAN ～よこはまつり～ takes place on September 20, 2021, at Yokohama Arena in Yokohama, Japan. This kickboxing event features Kenta Hayashi facing Daizo Sasaki in a super lightweight bout as a key matchup. Other fighters include Rukiya Anpo, Sina Karimian, and Hirotaka Asahisa across various weight classes. A special heavyweight bout marks Satoshi Ishii’s kickboxing debut against Ryo Aitaka.