The teenager who went missing during a dip in choppy waters off Rockaway didn’t know how to swim, a friend told The Post on Sunday.

Lamine Sarr, a 17-year-old high-school senior and aspiring model, had been playing the video game Fortnite with two friends Saturday afternoon when the trio decided it was too warm to be indoors and went to wade in the ocean around 5 p.m., a pal said.

“They were just gonna walk into the water,” said Ezra Cummings, 17, who has known the other boys since middle school.

The trio “never went in below their waist,” but then, “they couldn’t feel their legs” because the water was cold, Cummings said one of the boys told him. “After a little while they couldn’t feel their feet touching the ground, [they] turned around, and Lamine wasn’t there.”

One of the boys present during the outing told Cummings, “They could feel something pulling them away from the beach.”

The riptide risk was “high” Saturday — presenting “dangerous and potentially life-threatening conditions … for all people entering the surf” — according to the US National Oceanic and Atmospheric Administration, and the boys were swimming ahead of a 7 p.m. low tide.

There were no lifeguards on duty because the beach season ended a week before, on Sept. 9, according to the city Parks Department.

“They tried to fight it,” Cummings said. “They couldn’t. It pulled them out.”

Only one of the boys knows how to swim — and “barely,” Cummings said.

That teen was able to paddle over to a jetty, where he clinged to the rocks and began “screaming for help” while his two pals were pulled further from the shore, Cummings said.

“There was a bunch of people on the beach who ran over to help. They called the police, a few of them tried to swim out to get them,” he said.

By the time FDNY arrived, the Sarr’s two friends were already out of the water — but Sarr was nowhere to be found, officials said.

On Sunday morning, authorities resumed their search for the teen, who was last seen off Beach 86th Street.

Four uniformed NYPD officers combed the sand between Beach 84th and Beach 86th streets Sunday as two police boats and a Coast Guard vessel scoured the seas, supported by NYPD and Coast Guard choppers above. NYPD divers searched below the waves.

The “positive and cool” Sarr played in a band at Channel View School for Research in Queens and liked basketball and nice clothing, friends said.

“He liked the idea of people taking his pictures with fancy clothes,” Cummings said. “He wanted to be a model. He liked the idea of modeling as a job. That’s what he wanted to do after he graduated.”

Sarr was “always talking about graduation” and was looking forward to prom, said another friend, fellow senior Tenes Groves, 16, as she visited the area near Beach 86 with her parents Sunday morning.

“I know how loving he was and how open he was,” she said between tears.

Sarr’s mother is extremely distraught, Cummings said.

“She feels like his body is somewhere, washed up already, [that] somebody found him and rescued him,” he said.

“She’s not ready to believe he’s gone.”