Keep people and pets away from the otter. Call one of the marine mammal agencies listed below. Wildlife rehabilitation specialists will come and determine whether the otter needs help. If it does, they'll capture it and take it in for care. Not every otter you see on shore is ill or injured.
Females often come ashore to rest after mating.
They're also legally protected under state and federal endangered species acts and the federal Marine Mammal Protection Act. Only authorized wildlife rehabilitators are allowed to catch or move them.