At least two people drowned on the Garden Route over the Easter weekend.
The NSRI reported that the Wilderness duty crew were activated on Sunday, along with the SA National Park Rangers, the SAPS, and Western Cape EMS officials.
Wilderness duty controller, Mike Vonk, said a local man his forties got into difficulty and drowned.
"At 15h49, Sunday, 01 April, NSRI Wilderness duty crew were activated following reports of a drowning in progress in the Touw River Lagoon," he said in a statement.
"Our NSRI rescue swimmers responded to the scene and on arrival, it was confirmed that a local man aged in his late 40's, at a picnic with friends, had entered the water to swim when he got into difficulty."
"A friend had entered the water to try to help him but also got into difficulties and the friend was able to get out of the water unassisted and he was not injured but the casualty had at that stage disappeared under water," Vonk said.
He said two NSRI rescue swimmers entered the water and immediately started free-dive sweeping line search efforts. Vonk said they were joined by four other NSRI rescue swimmers who conducted a coordinated sweeping line search.
"During the search, the man was located and recovered from the water and the NSRI medical crew initiated CPR (Cardio Pulmonary Resuscitation) efforts and sadly after all CPR efforts were exhausted the man was declared deceased by EMS paramedics," Vonk said.
He said man's body was taken into the care of the Forensic Pathology Services and Police have opened an inquest docket.
Meanwhile, Vonk said that on Saturday, NSRI Wilderness, George Fire and Rescue Services, WC Government Health EMS and the SA Police Services responded to a remote location East of the Gwaing River Mouth following reports of an angler in the water and last seen drifting in a Westerly direction.
"Fellow anglers suspect that the local 49-year-old man fishing on rocks on the shoreline was washed off rocks by waves in the Spring High tide but no-one actually saw the man being swept off the rocks but he was seen in the water and drifting," he said.
"On arrival on the scene access to the remote area was hampered by darkness, steep inclines, and a remote, barely accessible location, and a search revealed no sign of the missing man".
"A search resumed from first light on Sunday including shore patrols and our sea rescue craft Spirit of Rotary engaged in a sea search and a Police Dive Unit are continuing in an ongoing search and recovery operation for the missing man," said Vonk.