A man believed to be an SANDF member from the Grahamstown military base is missing at sea off Port Alfred.
The NSRI said the 27-year-old was one of three men who swept out to sea in a rip current on Friday.
"At 19h10, Friday, 16th December, NSRI Port Alfred duty crew dispatched our sea rescue craft Rescue 11 Alpha and our rescue vehicle to West Beach following reports of men in difficulty in the surf reportedly being swept out to sea by rip currents," said national spokesperson Craig Lambinon.
"On arrival on the scene it was found that thre men had been swept out to sea by rip-currents. When two (of the) men managed to get out of the water they were treated by Holistic Ambulance Services paramedics for non-fatal drowning symptoms,” he said.
“Both men, aged 27, believed to be from a Grahamstown military base, were transported to hospital by ambulance in stable conditions for observation for secondary drowning symptoms and they are both expected to fully recover."
He said "an extensive search continued for one man who remained missing in the surf, aged 27, believed to be from a Grahamstown military base, but despite an extensive search no sign of the missing man has been found and the SA Police Services and a Police dive unit are continuing with an ongoing search operation."
Lambinon said police have opened an investigation into the incident.
He also said that earlier on Friday the NSRI Port Alfred duty crew responded to West Beach where a 17 year old male was in difficulty in the water.
"It is believed that the teenager was assisted out of the surf and he was transported to hospital by ambulance in a stable condition for observation for secondary drowning symptoms and he is expected to fully recover," Lambinon said.