There is a trance-inducingly beautiful beach in Thailand's Similian Islands so dazzling that to read a book or even speak while sitting on it feels wrong. Just iridescent turquoise water, sand like icing sugar, a jumble of granite boulders and a handful of dive boats anchored offshore. I hadn't believed beaches like this existed but on a Star Clippers sailing cruise through the Andaman Sea, they were two-a-penny, fringing islands that are mere specks of bottle green, inaccessible except by boat.

I boarded Stay Flyer, a graceful, four-masted, square-rigid sailing ship, in steamy Singapore with 100 other enthusiast, the kind of people who love sailing but would secretly rather sip a good rum punch than actually make the effort. The ship however, is the real thing, it's teak decks piled high with ropes, manned by a crew from Russian training vessels with bulging biceps from raising 36,000 square feet of sail everyday.

After a swift tropical sunset, Stay Flyer edged into the Malacca Straits, a minnow between the mammoth oil tankers and container ships, setting a course north alongside the Malay Peninsula.

Malacca, our first port of call, was a wonderfully crumbling colonial town and the best way to see it proved to be by rickshaw, a vehicle festooned with plastic flower garlands, an old car stereo dangling from the handlebars. We trundled past Chinese, Buddhist and Hindu temples, incense wafting through the warm air. The streets of Chinatown are lined with ancient shop houses, their peeling facades in faded oranges, pinks and greens, their goods piled high - herbs, bolts of fabric, antiques and tourist art.

Then it was on to Langkawi before a day at sea. Star Clippers always includes a day at sea in its itineries so I spent the next day sprawled in the huge, hammock like nets strung either side of the bowsprit (the pointy bit at the front), watching dolphins and flying fish.

Some passengers donned harnesses to climb the mast to the crows nest but I contented myself with with a Thai massage on deck, in a secluded area under a canopy. That night we crossed into Thai waters and woke up anchored off the green hillocks and white beaches of Koh Lipe, an island of astonishing beauty, habited by only chao leh, or sea gypsies; nomadic fishing people who originated from Indonesia and were settled on Lipe island at the beginning of the 20th century. Their life is simple , making traditional carved fishing boats, though a mobile phone mast occupied pride of the village centre where the only signs of life on a hot afternoon were pigs, goats, chickens and dogs scratching in the dirt.

The Similan islands, a day later, were the trip's highlight for me. People come to this tiny archipelago 60 miles north from Phuket to dive but just a mask and snorkel borrowed from the ships sports locker was enough for me. The colors of the reefs were psychedelic, water so clear I could see right across the bay to Star Flyers anchor chain. Whole communities of orange and white clown fish came to check me out. Electric blue surgeonfish fitted through scarlet corals, though a menacing grouper with not insubstantial teeth chased me away when I got too close to it's lair. I flopped onto the warm sand and lay there, gazing at the water.

Further north, Star Flyer glided into Phang Nga Bay, over which a forest of giant, sheer-sided limestone towers, or hongs, is scattered. After boarding the ships inflatable Zodiac launches, we squeezed through narrow caves into one of the hollow towers. the interior was a world of dappled green shade, monkeys rustling in the trees overhanging a muddy lagoon.

One island was surrounded by boats. It was one that was blown to smithereens (or not) in the seventies bond film The Man With The Golden Gun. Large parties of Japanese tourists lined up in a strike amusing Bond poses in front of villain Scaramanga's island hideout. Back on board, it was one more cocktail in the tropical bar, one more fiery sunset and, it has to be said, a few discreet tears as sails were raised for the last time and passengers realized that tomorrow morning meant Phuket and the end of the week of escapism.

By now, the floor of my cabin was covered in sand, I had lived in a sarong and a bikini for seven days and everything was stiff with salt, despite constant rinsing. My back was browner than my front from all the snorkeling and a fair few sandfly bites were emerging.

But it was the price I'd gladly pay again for sampling this small corner of pure paradise.