Another swimmer has gone missing in Long Island waters off Long Beach — days after a 10-year-old boy vanished while swimming there, officials said.

Authorities, including the US Coast Guard and the NYPD’s Aviation Unit, are searching for a 31-year-old man who was last seen swimming with friends near Long Beach Boulevard around 2 a.m. Monday, according to officials.

The man’s friends made it safely to shore and then called Coast Guard Station Jones Beach, notifying it of the situation, the Coast Guard said. A search effort was then coordinated with multiple agencies.

The identity of the missing man, who was last seen wearing a beige swimsuit and was described as weighing 170 pounds, was not immediately released.

The Coast Guard said in a statement that it “urges swimmers to always swim in areas where lifeguards are present. The ocean is powerful and can overtake even the best swimmers.”

The incident comes after a 10-year-old Hempstead boy, identified by News 12 Long as Ramel McCrae, went missing in the waters off Ocean Beach Park near Edwards Boulevard — not far from where the man disappeared.

The boy had been swimming unsupervised with his 11-year-old brother about 6 p.m. Tuesday before the siblings became separated, cops said.

The victim’s older brother made it safely out of the water.

Meanwhile, the body of a child was recovered from the waters off the coast of Long Beach on Sunday, and officials are working to determine whether it is the boy.