Palau

Palau is the country that wrote the playbook every other reef destination is now politely copying. The Palau Pledge — stamped into your passport on arrival, signed before you can clear immigration — was the first state-level visitor commitment of its kind in the world, and it set a tone that has since shaped the country's reef-shark sanctuary, the 80-per-cent-protected exclusive economic zone, and the mandatory reef-safe sunscreen rule that other tropical destinations are still pretending is too complicated.

The geography that justifies all this is genuinely uncommon. The Rock Islands are the limestone karst archipelago travel photographers can't ruin no matter how hard they try — 445 mushroom-shaped uninhabited islands rising vertically from a turquoise lagoon, jellyfish lake among them, and a UNESCO designation that is more usefully read as an operational policy than a marketing line. The diving is the country's most-discussed asset: Blue Corner, German Channel, the Ulong Channel for sharks at the cleaning station, and a wreck inventory from the WWII Pacific campaign that the country has chosen, deliberately, not to over-curate.

The hospitality stock is small and the right kind of small. Palau Pacific Resort and Palau Royal Resort handle the main island Babeldaob and Koror; the more interesting stays are the live-aboards (Sam's Tours, Solitude Adventurer) and the Carolines Resort over on Carp Island. There is no overwater-villa industry here, which is the point — the country has held the line against the development model that defined the rest of Micronesia, and the reef is the dividend.

November through April is the dry season; visibility from January through March is typically the best diving year-round. Manta-ray season at German Channel runs roughly December to April. The wet season from June onward is not a write-off — visibility holds, accommodation drops 30 to 40 per cent, and the country empties out — but plan around the typhoon track if you are sensitive to weather risk.