Fighting against the strong current, the four were pulled 300m out to sea within 10 minutes.
"When it started to sink we got worried ... we were able to stay calm," Mr Anaru said.
His father attempted to rescue them but almost flipped his own boat trying so went for help.
A man surfcasting off the point watched the events unfold and called the coastguard. Manawatu Coastguard sent out two jetskis to rescue the men.
"The Coastguard are the real heroes of this story," Mr Anaru said.
Manawatu Coastguard president Eddie Bambery said the men were lucky to be spotted as it was feared they wouldn't survive.
"Not even the best swimmers can fight the strong current. If nobody had been around to see the men in trouble, they probably would have drowned. People think they are bullet-proof but, they aren't, especially without a lifejacket.
"One of these days somebody will drown and it will be sad."
He urges people to check the tides, weather conditions and to never go out without a lifejacket on.
Sadly, the birthday boy had $300 stashed away in his wallet that now sits at the bottom of the ocean, but at least he has his life, Mr Bambery said.
Mr Anaru was clearly disappointed about the failed birthday celebration and loss of his boat.
"I guess we are alright and that is the main thing," he said.
The following day the small boat was spotted by a fishing vessel 2km out to sea and was reported. It was retrieved by the coastguard then returned to its Palmerston North owner.