'Incredible' close encounter with humpback as whales migrate north

Sydney's roads might still be quieter than usual but our humpback highway is as busy as ever.

Between now and August around 30,000 humpbacks will swim past our shores on their way north for winter before they make the return journey between September and November.

The humpback season normally begins in mid-May but due to coronavirus restrictions, operators like Go Whale Watching haven't been able to run tours.

This long weekend was the first time their boat was back out on the water and they were treated to a stunning show just off South Head.

"He played with us for literally 90 minutes, he just didn't stop, it was action the whole time," Simon Millar from Go Whale Watching told 9News.

"I say to people on the boat, it's pretty incredible that you've got the busiest city in Australia and you've got whales cruising past two kilometres outside of the harbour."

Mr Millar and wife Jessica are taking every precaution to keep passengers safe during the coronavirus pandemic.

"We've got highly reduced numbers that we're allowed to carry at the moment and we're also having to sanitise the boat and do a whole lot of extra steps to make sure everything is hygienic," Mr Millar said.

The husband and wife team also runs trips out of Merimbula on the South Coast, with that business hit hard following the bushfires.

"It hasn't been easy but I can definitely see light at the end of the tunnel now," Mr Millar said.

"It feels like we're starting to come out of the other side of it."

The team at Go Whale Watching says this will be a bumper year.

"If local Sydneysiders could get out there and support us, we would really, really appreciate it," Mr Millar said.