Jason Starling, director of Aquamarine Adventures and skipper of the cruise company's red boat Envision, said whale season this year so far had been "absolutely amazing".

"We typically say there's anywhere between 35,000 and 38,000 whales that make the migration each year but we've been saying that for about five years now. I think we're being modest with those figures," Mr Starling said.

"Seasonal counts charts the whale population as increasing by about 10 per cent each year. I would say that we're seeing closer to 40,000 whales travelling the humpback highway now.

"It's not hard to see whales, or to find them out on the water. If anything, you have to slow down, especially out past Fingal Island, because there's so many.

"Whales are one our greatest comeback stories. There was only a few hundred of them left before whaling was ended. Now they're tens of thousands of them."

Whale watchers on board Envision on the morning on Friday, July 9 were treated to a spectacular encounter.

The boat spent time with a pod of four humpbacks in the deep water off Fingal Island.

Passengers enjoyed 30 minutes of uninterrupted breaching (where the whale pushes out of the water, arcs and lands), tandem breaching (two whales breaching at the same time) and pectoral slapping (the whale lays on their side and slaps the water with their pectoral fin).

Mr Starling was at the helm of the boat, joined on board by crewmate and photographer Lisa Skelton.

Miss Skelton said the encounter with the pod was "pretty special".

"Breaching is obviously the behaviour that guests are most hoping to see each trip. To witness a 40 tonne animal lift itself clear of the water is an incredible sight," she said.

"Working on the water we can be pretty spoiled, especially when it comes to breaching but there's still some things that take our breath away like seeing that same behaviour executed in perfect synchronicity."

It is the peak of the northern whale migration, which began in mid-May and will continue through to August.

Hundreds of whales are passing Port Stephens daily as they head northern to the warmer waters of the Great Barrier Reef and their breeding grounds.

The southern migration takes place from August to mid-November when mothers and newborn calves make their way back down to the feeding grounds in Antarctica.

It is an estimated 10,000km round trip.

Mr Starling said whale watchers can expect to see calves and their mothers in the waters off Port Stephens in the "next couple of weeks".

While Aquamarine Adventures, like most Port tourism operators, faced a stream of cancellations ahead of the July school holiday, prompted by the Sydney COVID-19 outbreak and lockdown, business has bounced back thanks for local patronage.

Mr Starling said locals and Hunter residents have been taking advantage of their Dine and Discover NSW vouchers and that there are less crowds to book whale watching tours.

"The local support has been solid," Mr Starling said. "We've been going out on three trips a day, mainly with locals who haven't been out whale watching in years. This is the kind of support we really need going forward, local support."

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