Green turtle

The park is open year-round, but its two halves trade places. From roughly mid-May to early September, south-east winds make the southern sites and the crossing to them rough and hard to reach, while the sheltered north is at its best. From about mid-November to March the south is at its best, which is also the Manta Alley season, and some northern sites are more exposed. Day boats from Labuan Bajo work the north and central park year-round.

The atolls are a significant nesting, resting and juvenile development area, so densities are unusually high.

The hardest access window in this dataset. Roughly mid-March to mid-June only, which is why March and June read 'limited' rather than 'open'. Outside it the northeast monsoon (Nov-Mar) and southwest monsoon (Jul-Oct) make the crossing to an exposed mid-sea atoll unsafe. Nothing about the reef changes; you simply cannot get there. Boats sell out 9-12 months ahead as a direct result.

Near-guaranteed at Tongo Point and on the Panagsama house reef.

No closure. Both sources put the optimal window at roughly November/December to May; Jun-Aug stays good with fewer people; Sep-Nov drops in visibility and carries typhoon risk, which is why those months read 'limited'. The sardines are there regardless.

Year-round diving. The sources disagree on the best window: DiveIn recommends November to May and reports 82F water and 30m+ visibility in February; Bluewater prefers May to July for fewer crowds, warm water and staying ahead of hurricane season. Aug-Oct is the peak of Caribbean hurricane season and individual days or whole weeks get cancelled, which is why those read 'limited'.

Turtle Pinnacle is a cleaning station and the most consistent site.

Leeward coast, sheltered by the volcano. Diveable close to every day of the year. Winter swell restricts shore entries but not boat operations.

Diveable all year with no closure. Jun-Sep is the wet season with rougher seas, visibility down to 15-20m, and exposed sites like Peleliu frequently cancelled, hence 'limited'. Dec-Apr is dry season with 40m+ visibility and is also the manta window.

Diving and snorkelling continue year-round, but the whale shark tour fleet only operates March to June or August depending on the base, and the humpback swims July to October. Nov-Feb is the Australian summer wet and cyclone season on this coast with the megafauna gone, so those months read 'limited': the reef is still there, the industry is largely not.

Liveaboards run year-round. Dec-Feb is the wet season and cyclone window in Far North Queensland, when trips get cancelled and sea state deteriorates, hence 'limited'. The minke whale season is a hard two months, June and July, and those trips sell out a year ahead because only a small number of endorsed operators hold the permit.

Reliably seen on most wrecks; very large individuals on the YO-257.

South shore wreck diving runs year-round and is sheltered. North shore is seasonal in practice: winter (Nov-Mar) brings the swell Oahu is famous for and the Haleiwa tours cancel frequently. Because the wrecks are unaffected, the destination reads 'open' throughout, with the north-side caveat carried in the trip formats.