Some playful marine animals put on a show on both sides of the South Island at the weekend.

Seven humpback whales turned up at the Akaroa Heads on Sunday, in what Black Cat Cruises called the best whale watch experience in nearly two decades.

The whales put on a "magnificent" show for the guests for about 45 minutes, marketing manager Natasha Lombart​ said.

SUPPLIED Humpback whales are easy to identify and are well known for their spectacular breaching and beautiful, complex songs.

"Our skipper, Julian Yates, has been working at sea for 18 years and he said what he saw today was the best whale watch experience he has ever had," she​ said.

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"We had people from all over the world on the boats and they were all blown away."

Humpback whales are frequent visitors to New Zealand's coastal waters. They migrate between summer feeding grounds in Antarctica and winter calving and breeding grounds in tropical waters.

The Oceania population of humpback whales is classified as "endangered".

Humpback whales have a small dorsal fin with a distinctive hump at the front, knobbly protuberances on the head, tip of lower jaw and leading edge of extremely long flippers.

Their tail flukes are broad and have a unique black and white colour pattern, which allow individuals to be identified. They have a variable colour but are generally black with white on the underside and on the flippers.

Meanwhile, a pod of Hector's dolphins enjoyed an early morning surfing session at Ship Creek near Haast, New Zealand on Sunday.

Only found in New Zealand's waters, this distinctive grey dolphin with black and white markings and a round dorsal fin is the most easily recognised species of dolphin in New Zealand.