South Toms River is a borough in Ocean County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 3,643, a decrease of 41 from the 2010 census count of 3,684, which in turn reflected an increase of 50 from the 3,634 counted in the 2000 census. South Toms River was incorporated as a borough by an act of the New Jersey Legislature on March 28, 1927, from portions of Berkeley Township, based on the results of a referendum held on May 3, 1927.