Four students were injured when they were attacked near a ferry terminal following a night out in Portsmouth.
The men, along with a woman who was unhurt, were on a slipway by the Gosport Ferry when they were approached by three men at 0245 BST on Saturday.
Police said the attackers mistakenly accused their victims of attempting to assault them earlier in the evening.
One of the four students, who were all aged 19 or 20, suffered a broken collarbone.
The other men suffered minor injuries including a black eye, a bloodied nose and bruising to the face.
The three attackers were all described as white. One is described as about 25 years old, 6ft, with a stocky build and shaven head.
The second was described as about 23 years old, 5ft 10in, of medium build, with dark hair and wearing a pale blue polo shirt and shorts.
The third attacker is thought to be in his late 30s to early 40s, 5ft 10in, of medium build, and with dark but greying hair.