Scattered across the Andaman Sea, this enthralling marine park is the pinnacle of diving in Thailand. Staring at the colour of water alone will leave you spellbound, shifting in dazzling shades of blues and greens. Your best bet is to book a liveaboard, hopping from one outstanding dive site to the next, floating amongst kaleidoscopic reef fish and swirling schools of barracuda and snapper.

Nudging the Thai/Myanmar border, this collection of five dreamy islands, smothered in rainforest and haloed with bone-white sand is talked about in diving circles with sheer awe. Again, a liveaboard will take you to parts of the archipelago that feel untouched, dropping you at sites where seahorses peer out of crevices and whale sharks appear from out of the shadows.

Pitched 12km south of Phuket, Racha Yai is one of those easy breezy pinpricks drawing day trippers to wallow in its turquoise waters and dive offshore. Few people overnight here so it has that untouched sort of feel. And better still the diving is ideal for beginners, where you can hover above vast coral gardens and gaze at stingrays and shoals of barracuda.

Dive below the surface surrounding this enchanting limestone island and edge yourself along the vertical wall dropping into the abyss. Bamboo sharks drift in and out of sight, seahorses and frogfish cling to crevices and occasionally whale sharks emerge close by. If you’re an advanced diver, there are cracks and caves to swim through for the ultimate thrill.

True to its name, this site is carpeted with anemones, sweeping across the limestone pinnacle which makes it appear like one vast oscillating rock. Swim a little closer and you’ll spot clownfish, moray eels, lionfish and seahorses darting amid the soft corals. At times, the site is hampered by strong currents so it’s not one for the beginners, though it’s best to check with your dive team.

A little further from Anemone Reef is this 85-meter-long ferry wreck, now teeming with marine life. Once a car ferry, whittling passengers between Phi Phi and Phuket, it ran off course, hitting a reef and sank in 1997. Thankfully, there was no loss of life, and today experienced divers flip around this ageing vessel to gawp at the lionfish, bamboo sharks and leopard sharks drifting through its eerie atrium.

Stare at this site from above water and you’ll just see the pinnacle of a large monolith jutting out of the waves. Yet sink below the surface and three vast rocks plunge downwards, covered in coloured soft corals, sea fans and huge barrel sponges. And as the name suggests, leopard and bamboo sharks linger on coral ledges, lionfish float across the reef, and morays and pufferfish can all be spotted.

This small granite island looks like a giant rock that has been dropped into the sea. There are no beaches and no obvious places you can land. But cross to the western side and below the surface, a vast ridge hurtles into the water to a depth of 40 metres where divers come to stare at gathering squadrons of manta rays, fluttering like butterflies, above sweeps of colourful soft coral.