A playful juvenile humpback whale, which is believed to have been resting inside the Port with its mother, breached three times no more than 100 metres off the shores of Little Beach in Nelson Bay.

“It certainly was a great way to start the day,” Ben Armstrong, an engineer who was on board the Moonshadow-TQC cruise on Saturday morning, said.

“It’s not unusual to see whales in the harbour at this time of the year, during the southern migration. They use it as a refuge to rest up.

“The mother whale surfaced a couple of times but the calf decided to breach a few times.

“The passengers were thrilled. People love seeing humpback whales perform. They’re one of the most acrobatic creatures of the sea.

“It was a pretty good day for whale sightings, even after that. We saw quite a few whales off the islands.”

It was not just passengers who were enthralled by the show. Being a warm, sunny morning the beach was already filling up with families, children, boaties and jet skiiers.

Time stood still as people watched the show the calf and its mother put on, waiting for the creatures to leave the Bay.

In NSW, vessels are prohibited from entering the water within 100m of a whale or within 50m of a dolphin or dugong. The distance is between 30m and 100m for swimmers.

Mr Armstrong, who has been with Moonsahdow-TQC for six years, said there had been plenty of mothers and their calves sighted in the Port’s waters for the southern migration, which is now in full swing.

During spring, humpbacks journey from the tropical waters of the northern hemisphere to the southern hemisphere where they spend their time in Antarctica feeding.

“It seems like a good season for whales,” Mr Armstrong said.

“The northern migration was especially plentiful. The southern migration is still quite good. It’s a little patchy in spots, some whales seem to be going a little wider and missing Port Stephens.

“But we’ve seen quite a few mothers and calves using the harbour to rest up.

“It’s quite deep in the harbour there. It goes down about 16 metres off Halifax Park.”

Bonita Holmes-Nu'u, another Moonshadow-TQC crew member on board the Hinchinbrook Explorer for the 10am Saturday whale watching cruise, said all 70 passengers were “delighted” with the show.

“The mother and calf travelled past Fly Point to Little beach right at the time our vessel… was on her way out of the heads,” she said.

“The calf breached around the jetty three times, then travelled with mum in close past the beach, on the inside of the buoys.

“We were delighted to say the least.”

The skipper of Saturday’s cruise was Ben Lupton.

Ms Holmes-Nu'u and Moonshadow-TQC photographer Leanne Maffesoni caught the moment the calf breached.

The Port’s whale watching season runs from mid-May to mid-November.

Whale watching has embedded itself as a key winter attraction in Port Stephens, drawing close to 30,000 people to the region last year for guided tours and countless more to the coastline to see the creatures.

The direct impact the annual whale migration has on the Port’s economy is not known due to a lack of data.

However, whale watchers are believed to make up a significant portion of the 1.5 million people that visited Port Stephens in the year to September 2017 who spent $534 million.

Moonshadow-TQC welcomed 18,500 people on whale watching cruises last year and Imagine Cruises about 10,000.