A woman told officers she was attacked at about 12:45 a.m. on Lagoon Service Road near the San Rafael Stairs, police said.
Police say the suspect attempted to sexually assault the woman before fleeing on foot west toward Isla Vista, police said.
The suspect was described as Hispanic, 5-foot-7, approximately 25 years old, wearing a gray UCSB windbreaker with a hood, and dark-colored sweat pants.
Police did not say whether the attacker was armed or if the woman was injured.
Anyone with information on the attack is asked to contact the UCSB Police Department at 805.893.3446.
Police also issued a reminder to the community to remain vigilant and use the Community Service Officer (CSO) Escort Service, which is free and may be accessed by calling 805.893.2000 or police dispatch at 805.893.3446.