The man's wife, their toddler daughter and his brother were hospitalized after the incident, which occurred around 4:30 p.m. Saturday.
Park officials say 33-year-old Gonzalo Romero-Tlamintzi of Sea Bright was initially swept into the bay. His brother and his 30-year-old cousin, Miguel Angel Romero-Leon of Red Bank, tried to reach him, but all three were pulled under by the strong current.
Romero-Tlamintzi's wife, Natasha Tlamintzi, also swam out to help while holding their 28-month-old daughter. She made it safely back to shore with the child, but collapsed from exhaustion.
All five were taken to Monmouth Medical Center, where Romero-Tlamintzi and Romero-Leon were pronounced dead. The other three remained hospitalized Sunday.