Lucky Australian diver paddles five miles to shore with a tiger shark following him

It's a situation no ocean swimmer wants to find themselves in.

John Craig was free diving off the coast of Shark Bay in Western Australia on Friday afternoon, when he suddenly found himself alone — and stalked by a tiger shark.

Craig and a friend of his were at the last dive spot of the day, where a series of unfortunate events began, according to his Facebook post.

On his first shot spearfishing, he had managed to get his spear stuck in a rock. Meanwhile, his friend was on the boat, which was having mechanical trouble. By the point Craig managed to get his spear free, the boat had drifted away. He was alone.

"I started to call out and splash to try and get the attention of my friend but after five minutes it was clear I was on my own ... I had been splashing and screaming for some time and my heart rate was sky high," he wrote in the post.

Craig then dived underwater to check that he was in the same place as marked on the GPS, when he noticed a four-metre-long tiger shark approaching and circling beneath him.

"It was obvious the sharks had been attracted by my splashing and panicking so I knew immediately that I had to try to calm down in order to survive," he said.

After recognising the shark was trying to size him up, Craig decided to make a beeline for the shore. It wasn't going to be an easy swim, he was 7.4 kilometres (4.6 miles) out to sea. Then, the shark followed him.

"I have to admit that at this point I thought I was gone," he said. Fortunately, the shark swimming along with him gave up after about 500 metres in, and left him alone.

Craig kept swimming for about three hours before he noticed boats and a plane searching for him. He screamed and waved at them — but his wetsuit was in camouflage, making it difficult for rescuers to find him.

He made it to shore, exhausted from the swim and barely able to walk. The rescue boats and plane were too far for him to signal. Half an hour later, a plane came along the coast and circled to show that it had seen him. He was picked up by a fisheries boat, and reunited with his wife.

"I feel extremely lucky to be alive and was blown away by the Shark Bay community's efforts to rescue me," he added. "I am eternally grateful and I'm sure I'll be buying beers for years to come."

Despite the frightening experience, Craig doesn't want to discourage people from diving around Shark Bay.

"We need them in the oceans and as much as it was scary at the time I can only reflect on how beautiful that big female tiger shark was. If the circumstances were different I would have been stoked to have that experience," he said.