Footage has emerged of the dramatic rescue of a swimmer who was swept from rocks at Whaler's Way in South Australia, an area well known for its dangerous waters.

Key points: The 26-year-old man was swimming in a rock pool at Sleaford, near Port Lincoln

The 26-year-old man was swimming in a rock pool at Sleaford, near Port Lincoln A witness says the man was hit by a wave and "flushed out to sea" up to 500 metres

A witness says the man was hit by a wave and "flushed out to sea" up to 500 metres He was rescued by a commercial fishing boat after being in the water about an hour

The 26-year-old man had to be rescued after spending about an hour in the water at the southern end of Eyre Peninsula, near Port Lincoln, just after 5:00pm on Tuesday.

He had been swimming in a rock pool at Sleaford when emergency services received reports that he was struggling, after being washed into the water by a wave.

SA Police said the man was located and brought to shore by a commercial fishing boat about 6:20pm.

Unit manager for the Port Lincoln State Emergency Service (SES) Max Coulson said the man was "extremely lucky" to have been rescued so quickly and unharmed.

"Primarily my responsibility was getting crews out to him as quickly as possible," he told ABC Eyre Peninsula.

"The only information we had was that there was a person washed off a rock pool, 400-500 metres offshore."

A man stands on a rock at Whaler's Way where another man was earlier washed out to sea. ( Supplied: Ke Pin Peh )

Ke Pin Peh was a witness to the incident, and was filming and taking photos of swimmers in the rock pool from a cliff edge when he noticed the man in trouble.

He said the man was hit hard by a wave that had "engulfed him" after climbing up boulders next to the rock pool.

"The second wave was so huge that it actually overwhelmed [him] … I managed to catch the moment just before the wave engulfed him," he said.

"The next moment he's actually at the channel just next to the boulders, so he actually fell after the wave hits him."

He said the man tried to climb up rocks to safety but was hit again by another wave.

"That channel is like a drain so he literally got flushed out into the sea," he said.

"The next wave comes and he's tried to swim back but he couldn't find any way to get back up the rocks so after a few tries, he probably looks pretty exhausted."

The rock pool at Whaler's Way is popular with swimmers, but can also be treacherous. ( Supplied: Ke Pin Peh )

Mr Coulson said that was when the SES was called and rescue boats were sent to locate him.

"In between all of that there was a commercial vessel that happened to be in the area," he said.

"Fortunately, one of the cray boats was able to locate that person prior to the rescue boat arriving.

"Obviously we still had to get him back to land and assess him with the SA Ambulance Service."

SES repeats warning to swimmers

Mr Coulson said the man was in the water for about 45 minutes and it was lucky that he was able to stay afloat.

State Emergency Service personnel on the beach following the emergency. ( Facebook: Port Lincoln SES )

"The sea conditions weren't really bad, there was a bit of swell out there," he said.

Mr Coulson thanked all emergency services personnel and volunteers who came to the man's aid and said the incident should be a warning to swimmers in the area.

"The advice to everybody, we say this all the time, is never face your back to the sea conditions and don't go anywhere near the waters edge if you can see that the swell is up," he said.

"We don't want to keep seeing these accidents happen, whether it's a death or not.

"That situation yesterday could have easily changed."

Six people have died after being swept out to sea at Whaler's Way.

The latest incident occurred at a different spot to where a man and his daughter died in April.