Police arrested three men after a German tourist was beaten to the ground and kicked early on Tuesday morning by a gang on Beach Road in Pattaya.
The attack was caught on video. About 10 men were involved, police said. They were searching for the other offenders.
The video showed some of the men were dressed as motorcycle taxi drivers.
The victim of the assault was identified as David Lelonek, 40, a German. The attack was reported around 4am.
Mr Lelonek told Pattaya police via an interpreter that he did not know why they attacked him. He had managed to flee on a motorcycle to seek help.
Police said the victim had declined to press charges against the attackers, but they would take legal action anyway because the incident had damaged the city's tourist image.
Police said they had arrested three men allegedly involved in the assault. They were tracking down the others.
