The National Weather Service had warned of "life-threatening'' rip current and advised swimmers to stay away from unsupervised beaches.
Police say two other companions stayed close to the beach while the other two men swam about 50 yards out.
Two Suffolk County Park lifeguards on a daily workout run pulled one of the swimmers out of the water and administered CPR. The swimmer, a Brooklyn resident, later died at a hospital. The other swimmer was not found.