Snapper Rock at Mayor Island features dramatic lava columns and kelp forests. Located within the northern marine reserve, this site offers depths ranging from 5 to 50 metres. Access is by boat only, as the site is situated 35 kilometres from the shore. Conditions are variable, with moderate currents and potential surge. Due to the depth and current, this site is suited for advanced snorkellers. Water temperatures fluctuate between 15 and 22 degrees Celsius, though they may drop to 14 degrees. Divers and snorkellers should remain aware of boat traffic in the area.

Orongatea Bay at Mayor Island is a reef site characterised by a shallow rock platform featuring underwater hot springs that release bubbles. This marine location offers depths ranging from 2 to 50 metres, with an average depth of 8 metres. Access is by boat only, as the site is located 35 kilometres from the shore. Conditions are variable, with visibility typically between 11 and 24 metres and water temperatures ranging from 15 to 20C. Divers and snorkellers should be aware of strong currents, surf, and boat traffic. The site is suitable for beginners, though the depth and current require careful monitoring.

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.

Shelly Bay at Mayor Island is a sheltered reef site located within the Tauranga Harbour entrance. Featuring a crushed shell shoreline, the site offers shore access into calm waters with mild currents. It is suitable for beginners and those looking for a relaxed dive or snorkel experience. Water temperatures fluctuate between 15C and 22C throughout the year. Parking facilities are available for visitors. Divers and snorkellers should be aware of sharp coral present at the site.

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.

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.

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.

The Aldermen Islands, located 20 kilometres off the coast of Whitianga, offer diverse underwater topography including reefs, pinnacles, walls, and caves. Divers can explore depths ranging from 8 to 40 metres, with an average depth of 20 metres. Access is strictly by boat. Conditions are variable, with visibility typically between 15 and 30 metres and water temperatures fluctuating from 15C to 21C throughout the year. The site is suitable for beginners, though divers should be aware of potential hazards including deep water, variable currents, and low visibility. Species recorded around this area include wrasses, blue maomao, eagle rays, green moray, sea stars, snails, and chromis.