Willie, who wandered away from his family's car as they headed to Point Lookout on Saturday, was rescued, tired and exhausted, wading near a mudbank.

Willie's owner, JP Shelburn, said he had let the dog out of the car to have a drink of water, but within seconds he was gone.

"I turned around after getting our second dog, Clinton, out of the car and he [Willie] wasn't there. I started looking under cars and then I told the skipper that I thought our dog had gone overboard," Mr Shelburn said.

Mr Shelburn said the master of the 12.30pm ferry had made an announcement to other vessels to keep an eye out for a Willie.

"The ferry was turned around and we spotted Willie swimming in the channels and he had made it to a mudflat. He would have been in the water on his own for about 50 minutes," Mr Shelburn said.

"He was spotted by one of the water taxis and the master of the ferry authorised me to put on a life-jacket and swim out to get him.

"When we got back on the boat everyone was cheering and wanted a photo with him and I shouted everyone a beer.

"He was definitely scared and shaken."

Mr Shelburn said Willie was an adventurous dog.

Stradbroke Island Ferries Chief Executive Officer David Thomson said the rescue had been handled well.

"It is quite a big deal to turn a boat around and we empower our skippers to make on the spot decisions like these," he said.

"Master of the boat on the day, Bob Francis, coordinated the crew to do the right thing. The customers understood the situation and the reason for the delays, which were about 15 to 20 minutes," Mr Thomson said.

A passenger on the ferry, Shane McDermott of Wellington Point, said he had been taking visitors from Victoria over to Straddie when Willie went overboard.

"It was a heart-warming experience and we thought it was a great effort by the crew," Mr McDermott said.