The attack occurred at about 2:30am on Thaweewong Rd, within the busy Bangla Rd entertainment area, according to a report filed by Patong Police.
Patong Police Deputy Inspector (Investigation) Pol Lt Nonthawat Treekaew said officers were alerted at around 3am by the Bangla Special Patrol that a group of foreign men had been assaulted by several Thai men.
The injured tourists were identified as Pascal Werner, 20, Ben Vollmer, 19, and Jann-Arne Maximilian Buchlaub, 19, all German nationals. The three men were taken to Patong Hospital for treatment. The extent of their injuries has not been disclosed.
Police who attended the scene found that the attackers had already fled. No property was reported stolen.
Officers have begun reviewing CCTV footage in the area in an effort to identify the suspects and track their movements. Investigators are also preparing to interview those involved.
Patong Police Superintendent Pol Col Korakrit Khanthakrue confirmed that efforts are underway to locate and apprehend the perpetrators and that legal action will follow.