As of 3:18 p.m., officials said there had been an unconfirmed shark sighting on the beach and swimming was closed. The sighting was later confirmed to be an ocean sunfish.
Earlier in the day, beach officials put out a high tide warning at 4:20 p.m. Over sand vehicles at the beach are asked to use caution.
Both of the Duxbury Beach crossovers were open on Sunday morning along with the parking lot.
Beach officials are investigating the sighting. This is a developing story and will be updated with any new information as it becomes available.