But imagine coming across dozens of them between Moreton and Peel islands, off the coast of south-eastern Queensland.

Niki and Doug Feilding, who own Gold Coast boat building business Regatta Marine, had spent two weeks out on their boat and were taking a leisurely trip from Moreton Island to Peel Island when they spotted the herd.

"We dropped anchor in very clear shallow water and put the drone up," Ms Fielding said.

"I then rowed out to them in our eight-foot wooden dinghy.

"The water was super clear and I could see the bottom covered in starfish.

"It was an amazing experience with them surfacing all around the boat, totally unfazed by me being there.

"(There) didn't seem to be a lot of sea grass around in that area but they hung around for ages."

The seasoned Moreton Bay travellers were astonished to see the creatures together in a big group.

"It's a rare sight," Ms Fielding said. "I counted close to 100."

According to the Environment Department, Moreton Bay dugongs are mostly found on the Moreton and Amity banks, with some also sighted in Pumicestone Passage and the southern bay.

They often gather in herds of about 100. Moreton Bay is the southern-most place were dugongs are found along Queensland's east coast.

Moreton Bay dugongs travel as far north as Hervey Bay.