Three men have been arrested for robbery and assault after what police described as a "rare and violent attack" at Minehead beach on Tuesday.
The men, aged 23, 20 and 19 are alleged to have attacked two men sitting on the beach at around 0100 BST after befriending them earlier in the town.
A mobile phone and money were stolen in the incident.
Avon and Somerset Police said this was a rare incident and that there was only one similar crime reported last year.
Insp Lisa Simpson said: "This was a violent and premeditated crime, but it is fortunately very rare in west Somerset.
"The offenders targeted their victims and made sure they were in a vulnerable situation and robbed them. However, I am glad to say that this is an isolated incident and extremely unusual in this area."