An air, ground and sea search is continuing in a bid to find a young man who went missing at Glenelg beach while looking after a child with a disability.

Nischal Ghimire, 22, of Clarence Park, works as a carer and had been looking after a 10-year-old boy when he disappeared.

Mr Ghimire was last seen about 4pm on Thursday but was not reported missing until about 12.30am on Friday after the 10-year-old boy — who cannot speak — knocked on the door of a property on North Esplanade.

SA Police Inspector Sandy Morey said police were hopeful Mr Ghimire would be found alive.

“(Mr Ghimire) is the carer of a young boy, of about 10 years old, and they’ve come down in the heat of yesterday afternoon,” he said.

“The child has been located on the foreshore by nearby residents and a search has been underway since.”

Inspector Morey said police suspect Mr Ghimire had been in the water.

“The young boy indicated by his appearance that he had been in the water — whether the adult had been in the water as well, we don’t know at this point,” he said.

“Unfortunately the boy has a disability and is unable to speak so we’re not able to get any information from him as to what actually happened.”

Detectives talk to Zac Curnow, who found the boy when he knocked on Mr Curnow’s door just after midnight.Picture: News Corp Australia, Mark Brake/AAP
Mr Ghimire’s white Mitsubishi Colt hatchback remains parked on North Esplanade.

North Esplade resident Zac Curnow, 19, and his friends initially raised the alarm.

“About midnight we had a knock at the door ... and we opened the door and this kid was screaming and ran straight into our apartment. He was dripping wet and naked,” he said.

“He sat on the couch and we gave him a towel and ... rang the police. He looked pretty shaken up.”

Mr Curnow said officers and the boy’s mother arrived shortly after.

“(The mother) was distraught and crying,” he said.

“I’m just glad he’s home safe and the mum could be reunited with her son.”

A relative of Mr Ghimire, Devi Shrestha, 24, waited with other family members at the beach from early Friday morning, hoping for some good news.

“We didn’t know (he was missing) until 3am today when police arrived,” she said.

“We just tried to contact all his friends and all other people that he knows but didn’t find him anywhere. I’m feeling desperate — it’s been a long time.”

Ms Shrestha said Mr Ghimire “loved it at the beach” but was not a swimmer.

“He doesn’t know how to swim,” she said.

Mr Ghimire is Nepalese with a dark complexion and was wearing a T-shirt, long pants and glasses.

Police ask anyone who saw Mr Ghimire at the beach or has information on his whereabouts to call the police assistance line immediately on 131 444.

Surf Life Saving SA spokeswoman Mel Davis-Bishop encouraged people to be vigilant when at the beach.

“As always, we urge the public to always swim between the red and yellow flags at patrolled beaches,” she said.

Ms Davis-Bishop said people should also follow any safety signs at the beach and be aware of their own skill level when it comes to swimming.