Red Beach, Santorini, Greece

A crescent-shaped island in the middle of the Aegean Sea, Santorini was once a massive volcano – archaeologists say it blew its top way back in the Bronze Age. It left behind a fascinating place where whitewashed buildings cling to the edge of towering sea cliffs, and beaches come in many colours, including black, brown, white and even red. At Red Beach, iron-rich sands – and the cliffs that hem them in – have taken a curious and beautiful rust-coloured hue, which forms a stark contrast when they intersect with the beach’s deep blue waters.
Whitehaven Beach, Whitsunday Islands, Queensland, Australia

While the pristine, azure waters of Whitehaven beach on North-East Queensland’s Whitsunday coast are superlative-worthy in themselves, it’s the sand that really makes it unforgettable. Soft and blindingly white, it is made of almost 98 per cent silica – a mysterious geographical phenomenon that scientists can’t explain – but that you simply have to experience burying your toes into. While the waters are divine to swim in year round, it’s worth remembering that stinger season is from October to May, when warmer waters attract larger numbers of Box and Irukandji jellyfish – a stinger suit is recommended for extra protection.
Blue Lagoon, Fiji

In many ways, Fiji – a cluster of 330 islands in the South Pacific – is the ultimate paradise, an almost mystical place where the palms seem taller, the water always feels bathtub warm, and coral reefs extend themselves and their aquatic bounty before snorkellers from all over the world. While pretty much any spot in Fiji would do for a dip, one of the most beautiful places you can swim is the remote Blue Lagoon. Part of the Yasawa Islands, Blue Lagoon is a spot where the water seems bluer, the often empty beaches appear whiter, and the aquatic wonders, from starfish to seahorses to sharks, are truly mind-boggling.