Te Whanganui-A-Hei Marine reserve

Since becoming a protected area, the marine life around Cathedral Cove is thriving. We exclusively offer the chance to view this magical underwater world whilst our tour. The glass panels on all our vessels provide a window to view the marine life from the comfort of the vessel.

Te Whanganui-A-Hei became a marine reserve in 1992 and is New Zealand’s sixth marine reserve, the first for the Coromandel. With no recreational or commercial fishing allowed inside the reserve, marine plants and animals are free to return to their natural balance. Marine reserves have been hugely successful in restoring marine ecosystems, including fish stocks, in other parts of New Zealand. The reserve covers nine square kilometres and is administered by the Department of Conservation in partnership with the Te Whanganui-a-Hei Marine Reserve Committee.

Gemstone Bay Snorkel Trail - What is it?

A snorkeling trail has been set up at the marine reserve to encourage swimmers to explore the marine life. The snorkeling opportunities in Te Whanganui-A-Hei Marine Reserve are outstanding, especially at Gemstone Bay and the western side of Mahurangi Island.

Four marker buoys with information panels depicting which species inhabit each area are anchored from 50 to 165 metres offshore. For example at buoy three, snorkellers can expect to see marblefish, butterfish & red moki hiding in a seaweed city.

Snorkelling Options

The Glass Bottom team knows all the best snorkel spots both inside and outside the marine reserve. We provide quality snorkel equipment which is available on the boat, free of charge.

The skipper will decide on the day which snorkel spot to choose. Factors such as weather, snorkelling skill levels, water clarity and where the marine life has been spotted last are all contributing factors towards choosing the best spot, ensuring every snorkel experience is awesome!

If snorkelling isnt your thing, that’s completely fine as you can experience the same thing as the snorkelers while sitting back and watching the marine life through the glass panels. There is something for everyone on the cruise.

What will I see?

Since there is no fishing in the reserve the fish life is plentiful. In Gemstone Bay you will be snorkelling amongst a big school of snapper. While in Gemstone bay and other snorkel spots keep your eyes out for blue cod, trevalley, red moki, wrasses, goat fish, blue maomao, demisels, crayfish, kina, stingrays and more. Snorkel around the boulders covered in different species of kelp and soft corals. Explore the small caves, overhangs and kelp forests which are full of marine life.

The marine reserve is administered by the Department of Conservation in partnership with the Te Whanganui-a-Hei Marine Reserve Committee.

The Friends of Te Whanganui-A-Hei Marine Reserve Trust was established in 2010, primarily to raise funds for the marine reserve. The Trust receives funds through grants and donations. One of the main reasons for setting up the Trust was so that funds could be raised to develop the educational potential of the reserve.

If you would like to help out, donations can be made to The Friends of Te Whanganui-A-Hei Marine Reserve Trust.


Please click on the link to make donations or for further information.


16 Monk Street, Whitianga, New Zealand.

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