Okaparu Reef is a fully submerged rocky garden spanning five acres off Mayor Island. The site features an upper surface at a depth of 5 metres, with the reef extending down to 40 metres. Due to the presence of moderate currents, surge, and significant depth, this location is suited for advanced snorkelers. Access to the reef is by boat only. Water temperatures at the site fluctuate between 15C and 22C throughout the year. Snorkelers should be aware of hazards including the deep water, sharp coral, and strong currents present in the area.

Astrolabe Reef (Ōtāiti) is a prominent marine site located 22 kilometres from the shore of Mayor Island. The site features a reef system that rises to a minimum depth of 8 metres, alongside the wreckage of the MV Rena. Due to the depth range of 8 to 70 metres and the presence of strong currents, this site is suited for advanced divers. Access is strictly by boat. Divers should be aware of potential hazards including entanglement, sharp coral, strong currents, and surface surf. The site offers a varied topography for exploration, though conditions can be variable.

Motunau Island is a volcanic site located 12 kilometres off the coast of Mayor Island. The topography features a narrow channel separating two portions of the island, with reefs and pinnacles providing a varied underwater landscape. Divers can observe deep-water cup sponges and hydroids at very shallow depths. Access to this site is by boat only. Conditions are variable, with moderate currents, surge, and potential surf. Due to these environmental factors, this site is suited for advanced divers. Snorkellers may also enjoy the site, which holds a 5/5 rating for the activity.

Rabbit Island, situated 500 metres from the shore of Mayor Island, features a diverse underwater landscape composed of natural reef structures and artificial reef elements. The northern side of the island is defined by fringing rock outcrops. This site is suited for advanced divers, as it is subject to strong currents and potential surf conditions. Depths at the site range from 5 to 30 metres. Access is available via both shore and boat entry. With water temperatures fluctuating between 15C and 21C, the site is also suitable for snorkelling, holding a rating of 4 out of 5.

Moturiki Island is a shore-accessible reef site located off the main beach of Mount Maunganui. The topography features rocky shores and remnants of an old aquarium wall, which now functions as an artificial reef structure. Depths start at 1 metre, making the site suitable for beginners. Conditions are variable, with mild currents and potential for surf and surge. Divers and snorkellers should remain aware of boat traffic in the area. Parking is available for visitors. The water temperature ranges from 15C to 22C throughout the year.

Karewa, located off Mayor Island, offers a combination of reef and wreck diving. The site features depths ranging from 10 to 22 metres, with an average depth of 15 metres, making it suitable for beginner divers. Access is by boat only, situated 6000 metres from the shore. Divers can expect visibility between 5 and 10 metres. While currents are generally mild, they can strengthen without warning, and surf conditions at the entry point may vary. Divers should confirm local conditions with a charter operator before departure. The site is accessible year-round, with water temperatures fluctuating between 15C and 22C throughout the year.

Anzac Bay Rocks at Mayor Island is a rocky reef site offering shore access suitable for beginners. The topography consists of rocky points that provide a sheltered environment for both diving and snorkelling. Divers and snorkellers may encounter snails, which are very common, alongside uncommon sea stars, red comb stars, and crabs. Rarer sightings include the common Sydney octopus, scorpionfish, sea squirts, and the bronze whaler shark. Water temperatures fluctuate between 15C and 22C throughout the year. Be aware that conditions can include moderate currents, jellyfish, and periods of low visibility. Toilets are available at the site for visitor convenience.

Turanganui Point at Mayor Island features a reef and pinnacle structure with significant vertical relief. The site drops from 20 metres to depths of 80 metres, with an average depth of 30 metres. Divers experience moderate currents and surge, requiring comfort in moving water. Visibility typically ranges from 10 to 30 metres. Water temperatures fluctuate between 14C and 18C, necessitating appropriate thermal protection. Access is exclusively by boat, and divers must remain vigilant for boat traffic during surface intervals and ascents. Guided tours and boat charters are available to assist with navigating local conditions and swell.