Are dogs allowed to swim in the “beach” área as well?

Yes

Dogs are allowed in most areas of the park. They ARE NOT PERMITTED in the beach areas. The areas where pets are NOT PERMITTED are : Smithfield and Milford Beach between Memorial Day and Labor Day Raymondskill Falls and Dingmans Falls George W. Childs Park Valley View Group Campsites Hidden Lake Hialeah Picnic Area McDade Trail from milepost 1.0 to milepost 2.5 (from June 1 to September 8). Just read the National Parks Service website, people.