The man, Wanchai, 37, died in Thepkassatri Road, Phuket's mainnorth-south artery, about 8.08pm.
Police believe the men were on the way to a wedding at a workers' camp site. A bottle of Blend 285 whisky was found at the scene.
Police think speed was the problem rather than drink. A helmet was found at the scene but police were unable to say whether it was being worn.
The men were riding a red-plate Honda Wave.