Lifeguards prohibited swimmers and surfers from entering the ocean between Newport Pier and 56th Street "as a precaution," according to the City of Newport Beach's Twitter account.
As of 8 a.m. Thursday, ocean access was reopened.
The city, in a tweet, noted that the shark, which was originally sighted about 200 yards off 36th Street, appeared to just be swimming and "not acting aggressively."