Off the North and South Islands, dive sites are scattered among subtropical islands, with kelp forests and cold-water fiords.
The wreck of Greenpeace's Rainbow Warrior, the Poor Knights Islands' maze of archways and caves, Fiordland's spectacular red and black corals and organized swims with dolphins and fur seals are all there to be explored.
You might also be lucky enough to spot elephant seals, penguins and whales.