Astrolabe Reef / Otaiti is 12 Nautical Miles or 22 kilometres from the entrance of Tauranga Harbour. It takes just under an hour to reach the Reef, depending on conditions and boat size / speed. GPS Coordinates for Astrolabe Reef are 37° 32.439’ south and 176° 25.692’ east.

For safe boating, skippers should know the forecast and follow safe boating practices at all times. Boats less than 5m in length are not encouraged to visit the Reef for safety reasons. Learn more about general safety information, marine broadcasts and other useful information, including Maritime New Zealand’s Skipper Responsibilities information.

If you haven’t visited Astrolabe Reef before, it is strongly recommended that you speak with one of the local fishing, boating or dive retailers or clubs as part of your planning, or join an organised trip so you are in good company. Check out a list of local clubs and charters.

For people intending to dive, it is important to understand that Astrolabe Reef is a technical, open ocean site with depths beyond recreational diving limits. Learn more about diving at Astrolabe Reef and the two suggested dive sites.

Maketu Coastguard (vessel – Reef Watch) will be the onsite advisor at the Reef, when conditions allow, during the initial opening stage. The onsite advisor can provide information, monitor activities and assist visitors as needed.

Maketu Coastguard - Eastpack Rescue Vessel

Local Area Marine Chart

What to Expect Onsite

There are a number of potential and significant hazards that visitors to the area should be aware of.

Large numbers of vessels are likely to be visiting the Reef, particularly during the warmer months, weekends and public holidays. Skippers should always look out for surrounding boats, the Reef and also the likely presence of divers and snorkelers in the water.

The tip of the Reef is a rocky pinnacle which rises up 75m from the surrounding seabed, breaking from the surface at low tide. The Reef has varied underwater topography including gullies, plunging walls, shelves, caverns and caves. The Reef is regularly subjected to a prevailing strong northerly swell, currents are unpredictable and wind conditions can be strong and change rapidly (particularly the prevailing west and southwest winds).


The Rena wreckage is fully submerged and no longer poses a risk to navigation. It occupies less than 2% of the total Reef area, and can be categorised into three parts of wreckage:

  • The bow section, which lies east to west near the peak of the Reef, at a minimum depth of -1m (LAT). Dive Site 2, trail 2C loops around its perimeter. The closest reference point onsite is the Dive Site 2 orange mooring buoy.
  • The separated bow pieces (including bow thruster), which lie on the southern side of the reef. Their approximate location is marked onsite by the Dive Site 1 orange mooring buoy.
  • The stern section, which lies on the eastern side of the Reef, and is marked onsite at either end by two yellow buoys. Due to its depth diving the stern is NOT recommended.

Astrolabe Reef and the location of the wreckage (March 2015].


BIRD'S-EYE VIEW OF WRECKAGE and dive sites 1 & 2

Safe Boating Reminders

  • Always check the marine forecast before setting out.
  • Vessels less than 5m in length are not encouraged to visit Astrolabe Reef due to the conditions being unsuitable for small boats.
  • All vessels should carry a 406MHz EPIRB (Emergency Position Indicating Radio Beacon).
  • Ensure you have enough life jackets / flotation devices of the right size for everyone on board. Wear your life jackets at all times.
  • Inform someone onshore of your trip, including your return time.
  • Skippers can report trips to the Coastguard on Channel 83.
  • Boats with divers in the water must fly an A Flag (diver’s flag). This must be 600x600mm minimum in size and divers must remain within 200m of this dive flag.
  • No person shall propel or navigate a vessel (including a vessel towing a person or an object) at a speed exceeding 5 knots:
    • Within 50m of another vessel, raft, floating structure, or person in the water; or
    • Within 200m of any vessel or floating structure that is flying an A Flag of the International Code of Signals (diver’s flag).
A Flag

A Flag

Helpful Boating Information


  • VHF Channel 83 – Coastguard broadcasts hourly marine forecasts.
  • SeaComs channels 3 and 24 are used by many local skippers.
  • VHF Channel 6 is also used by local skippers.


  • VHF Channel 16 is the international channel for maritime disasters and hailing (calling).
  • Dial 111 in the case of an emergency.



Distress, Urgency & Safety Calls

Special calls are used in distress, urgency and safety, and must be properly understood and used correctly.

Use VHF Channel 16 to make a call.


The radio-telephone distress signal MAYDAY is used to indicate that a vessel, aircraft or person is in grave and imminent danger and requires immediate assistance.


The radio-telephone urgency signal PAN PAN is used to indicate that a vessel has a very urgent message to transmit about its safety.


The radio-telephone safety signal SÉCURITÉ (pronounced say-cure-ee-tay) is used to indicate that the calling station has an important navigational or meteorological warning to transmit.