While the Delaware River spans multiple states, the best and safest places to swim in 2026 are within the Delaware Water Gap National Recreation Area in New Jersey and Pennsylvania. Official designated beaches like Milford Beach and Smithfield Beach offer monitored areas with ropes and life jackets, which are highly recommended due to the river's unpredictable currents. In the upper Delaware, the water is generally cleaner and clearer, making it popular for "tubing" and casual wading. However, it is a critical peer-to-peer warning to never swim in the tidal sections of the river near Philadelphia or Wilmington; the water quality in these urban zones often exceeds safe bacteria levels due to runoff, and the commercial shipping traffic creates dangerous wakes. Even in "safe" zones, the river bottom can be incredibly rocky and slippery, so wearing water shoes is mandatory. By 2026, the "River Report" apps provide real-time updates on water temperature and flow rates, which you should check before heading out, as the river can become dangerously fast after heavy rains in the Catskill Mountains.