Adrift from the crowd

Accompanying me and 20 other tourists on his signature Hong by Starlight excursion, he admits feeling guilty about how busy the bay has become and explains he is trying to encourage the industry to "green up" by educating guides and encouraging them to collect floating rubbish.

"Be careful - what you're standing on there is the mangrove's lungs," he says, pointing at the little nubs of root sticking up from the mud, as we squelch over one island's interior. "I've seen photos of people doing pull-ups on the branches. Please don't touch."

The excursion's selling point is that each person has his own guide to paddle the kayak and point out wildlife - monkeys, birds and lizards - while exploring several stunning lagoons. As dusk falls we eat a delicious buffet of curries on the deck of the big boat that ferries us between kayak spots and make kratongs, floating offerings of flowers and candles, that we release to bob about a starlit lagoon. It's romantic but a tad schmaltzy and being paddled by the guide feels cossetting. Ideally, one would explore the bay independently but local operators won't rent kayaks to inexperienced tourists without a guide because of dangerous currents and complicated tides, so I booked an extended camping and kayaking "mini expedition".

While the rest of the travellers head back to Phuket, our small breakaway party - with leader Olay, Welsh guide Martin and assistant Pung - paddles into the darkness.

We set up camp on a tiny stretch of beach backed by towering cliffs on Koh Penak and park our kayaks in front of our tents. Blinded by each other's head torches, we drink beer around the fire and listen to Martin's tales of expat life - like the time he discovered a curled-up cobra in his bed and hired a snake-charmer to move it.

Phosphorescence glittering in the warm sea draws us in for a late-night swim and we float on our backs looking up at the stars, flipping over to create our own underwater constellations; we fill bottles to make "sparkling water".

At dawn I unzip the tent and watch a violet-rose-red sunrise on the sand. Between looming hulks of limestone across the bay, long-tail boats cast the day's first nets while around me the island wakes up. Insects buzz in the greenery; freshly filled rock pools fizz. I watch a trio of hornbills flee squawking from the trees and a metre-long black monitor lizard slither into the sea from the rocks.

At breakfast - fresh pancakes and scrambled eggs - Olay describes how he had to rescue the kayaks in the middle of the night from the high tide that lapped at our sandy doorstep.

Eventually we set off, each paddling our own kayak, following the tide east into the bay. We stop to examine quivering red anemones, explore Hong Island, a glittering "diamond cave" and watch monkeys. Before heading into open water to paddle from island to island, Olay adjusts our route to circumvent the currents. In the main channel, pleasure boats chug past blasting their horns and are loaded with tourists bound for Koh Ping Kan - "James Bond Island", the setting for Scaramanga's lair in The Man with the Golden Gun. We stop there, too, walking along a path to see the famous limestone stack just a few metres out in the water, where dozens of tourists - Japanese, French, German, Australian - pose, fingers pointing like guns. Yet with so many islands, it isn't hard to find deserted places to swim and if not by kayak you can reach them by chartering a long-tail boat. We see many tiny beaches where the company sometimes camps, though Olay insists some islands are forbidden to all but licensed bird-nest collectors, who sell the valuable ingredients for soup and are allowed to shoot anyone who encroaches on their territory.

Riding the tide back to camp, exhausted after seven hours of kayaking, we return to find Toy, a chef, working in a makeshift kitchen set on some stones: spicy tom kha gai soup, curry, noodles and sweet-and-sour jackfish, freshly collected cockles and chillies.

Phang Nga is so vast, it would take weeks to paddle across; to be sure we see the highlights, a long-tail boat takes us around the next day. At "Tarzan beach" we swing on vines from rocks into the sea; see huge shoals of anchovies and several cigar fish; drift silently listening to monkey calls; and explore Hlam Tang, the largest hong yet, negotiating a thick maze of mangroves to a huge, other-worldly cavern full of dripping stalactites. Later, squatting among life jackets and paddles below deck, Toy cooks the best green curry I've had in Thailand - "pet pet pet!" ("very spicy!"). Snorkelling later to a long sandy spit that protrudes from the beach on Koh Pak Beer, I float above large sea urchins, brain coral, giant clams and parrotfish, and almost step on a stingray in the shallows.

Koh Yao Noi, the bay's second-largest island next to its neighbour, Koh Yao Yai, is my drop-off point. With its tiny villages, beach huts, massage stalls and rubber farms, it looks traditional and unspoilt, despite the smattering of top-range hotels. But as the long-tail pulls up at the immaculate lawns of the Koyao Island Resort, I know a sea-view room will never match the magic of a plastic tent on a deserted strip of sand.

FAST FACTS

V Australia flies non-stop to Phuket (8hr 45min) from Melbourne for about $900 return including tax; Sydney passengers pay the same and connect in Melbourne.

John Gray's Sea Canoe runs a range of tours, including a three-day camping trip from THB20,200-57,800 ($750-1950) a person, depending on group size, and the Hong by Starlight trip for THB3950 a person. See johngray-seacanoe.com.

- Guardian News & Media