When a group of jetskiers stumbled across a green sea turtle during a tour of Magnetic Island, Andrew Eslick panicked, thinking the creature was dead.

Mr Eslick was leading a tour around the island's beaches and initially assumed the creature was sunbaking.

"We get closer to it and I think, 'Oh no, this turtle's not moving. I think I'm about to show everyone a dead turtle,'" he said.

But as he reached out to pat the turtle on its head, it opened its eyes.

It became clear the animal was "unhealthy and weak".

"Her shell started having little bloody patches all over it where her shell had become soft and started to peel off like wet paper," he said.

Mr Eslick asked the group if they wanted to stop the tour at Maud Bay beach to save the turtle.

They insisted on helping and secured a lifeguard ski from a nearby area.

Mr Eslick's three-year-old son, who was part of the group, dubbed the turtle 'Princess Peach'.

"It took a bit of a group effort to get her onto this board because she weighed over a hundred kilos, she was a big turtle," Mr Eslick said.

"We finally got her onto … the ski, and we made our way back to Horseshoe [Bay].

"That's where the turtle hospital people were waiting for us, and they took care of the rest from there."

It was only six months ago that Mr Eslick rescued another turtle, dubbed 'Betty'.

"We handed her over to the turtle hospital," he said.

"When we brought Princess Peach in, the turtle hospital was like, 'Far out, every time you bring us a turtle, it's getting bigger and bigger.'"

Magnetic Island Network for Turtles rehabilitation clinic coordinator Lily Donnelly is helping to take care of Princess Peach.

She said besides infectious lesions it was a healthy turtle that could be anywhere between 50 and 80 years old.

"We're actually still trying to find out what the causative agent of her infection is, but she is healing well in care," she said.

Ms Donnelly said less than 12 weeks was the standard time for turtle recovery.

"We try to get them out as soon as possible to keep them wild as possible," she said.

Ms Donnelly said once the turtle had healed, it would be tagged for future monitoring.

"All turtles under Queensland government regulations are tagged," she said.

Mr Eslick said he was pleased his customers chose to stop and help.

"That's what we're all about on the island, making sure we look after the water and look after our animals in this area."