Referred to as the “Galapagos of the Indian Ocean”, it is the site of the famous annual red crab migration as well as home to rare birds and turtle-nesting beaches.

Diving on pristine reefs and drop-offs is possible year round, says Diverse, with reef sharks all year too and whale sharks from November to May.

The tour operator also reckons Christmas Island is a good destination to combine with a trip to an Indonesian dive-location such as North Sulawesi, Bali or Raja Ampat.

It charges from £1999pp for a package consisting of flights from London via Jakarta (30kg baggage allowance), seven nights’ accommodation (two sharing), 10 guided boat-dives with Extra Divers, one night’s B&B in Jakarta and all transfers.