YESTERDAY'S 5.8 magnitude earthquake wasn't just felt on the Whitsunday mainland.

Staff at Cruise Whitsundays have said it was felt in the waters around the Great Barrier Reef.

General manager operations Gary Kilby said  divers reported they felt vibrations under the water.

"Our crew on board Seaflight said they thought the engineer must have been starting up the boat's engines, as they felt a strong rumbling through the hull and heard what they thought was the sound of the engines turning over," he said.

Although the earthquake was felt in and above the water, Cruise Whitsundays staff didn't realise straight away what they were dealing with.

"Crew members on the Reefworld pontoon also reported feeling vibrations," Mr Kilby said.

"It wasn't until we were cruising back to the mainland and came into phone reception that we heard reports of the earthquake, and then started comparing stories (and that's) when we realised that's what it was that we'd all felt.

Other parts of the Cruise Whitsundays operation were also affected.

"Even our vessel Kingfish, under full steam cruising around Pioneer Rocks back into Port of Airlie from Daydream Island, felt a strong a vibration," Mr Kilby said.

"The skipper actually slowed the boat to a stop thinking he had caught something in his props," he said.

"It was certainly one of our more unusual days on the water, that's for sure."

Thankfully Mr Kilby was able to confirm there hadn't been any damage to the reef, corals, "or any of our infrastructure at the reef".