Video evidence obtained from a security camera in Patong enabled police to see what happened.
Authai Sesang, 27, was arrested quickly at his apartment in Soi Nanai thanks to the compilation of details about all tuk-tuk, taxi and motorcycle riders under the Patong Safety Zone scheme.
Police named Thomas James, 40, and Darren Johnvose, 32, as the two British tourists who were the apparent victims of the assault.
The dispute took place in Soi Sansabai about 11.30pm. Investigators are now tracing other men involved, Patong police said.
Police in Patong also staged a surprise checkpoint on the road behind Jungceylon last night, checking all vehicles for drugs and weapons as part of the Patong Safety Zone project.