As Chapman surfaced from the water, his GoPro captured the moment he exclaimed in disbelief, “Where on earth is the boat?”

Realizing the gravity of the situation, he shouted to his companion, “Hey, the boat … it’s drifted off its anchor!”

In an interview with 9News, Chapman recounted his initial thoughts, saying, “At first, I feared the boat had sunk, so I frantically searched for it.”

He continued, “Then reality hit me hard. What do we do now? This is probably every diver’s worst fear—losing your vessel.”

Fortunately, they noticed another boat in the distance, although it was approximately a kilometer away.

The pair spotted another boat but it was about a kilometre away.

“I reckon we just try and swim closer to them, bro, and then we’ll yell,” Chapman says to his mate.

An hour and a half after first entering the water the pair were finally spotted.

They were brought safely on deck and eventually tracked down their own vessel.

“A lot of swear words of relief … I think that came from everybody,” rescuer Tahnee Forster said.

The rescued men have since realised they made two major mistakes yesterday: not securing the anchor with the correct knot and diving without a skipper on board.

“Especially in hindsight thinking about … like all jokes aside, it could have gone terrible, it could have been a lot worse than it actually was,” Chapman said.

“If you are gonna go out without a decky, make sure you know how to tie knots I guess.”