Kubota Spears Funabashi Tokyo Bay is a Japanese rugby union team based in Funabashi, Chiba participating in the Japan Rugby League One. The team rebranded as Kubota Spears Funabashi Tokyo Bay ahead of the rebranding of the Top League as the Japan Rugby League One in 2022.

Japan Rugby League One is a rugby union competition in Japan. It is the highest level of professional rugby competition in the country. The Japan Rugby Football Union created the competition in 2003, by absorbing the Japan Company Rugby Football Championship, to drive up the overall standard and popularity of the sport and improve the results of the Japan national rugby union team. The chief architect of the league was Hiroaki Shukuzawa who strongly felt the urgency of improving Japanese domestic company rugby to a professional level which would allow Japan to compete more convincingly at Rugby World Cups.