Sazlul Kabiri, 22, of Queens, was on his water scooter at 1:51 p.m., about 300 yards south of Swan Creek, when it overturned, Suffolk police said in a news release.
Jeffrey Wetzel, 41, of East Patchogue, was on the beach at the time and "heard Kabiri shouting in the bay and swam out to him on a boogie board," police said. "The two men waded in the water and began shouting for help."
Marine bureau officers Robert Femia, Christian Schnoor and Robert Jenkins, in a police boat, responded to a 911 call of distressed swimmers and pulled the men from the water, police said.
In the news release, police did not say whether either man was wearing a life jacket.