I arrived at about 9pm and Patong Beach was just getting going. By the time I had checked into my room, it was seething. I had never seen such a compressed mass of bars, restaurants and shops.
On the pavement, enterprising Thais were offering to sell everything from cigarettes to sarongs. Tourists of all nationalities crowded past on their way between bars or, like me, just taking in the sights.
In the narrow road, tut-tut taxis hooted at each other. Mopeds weaved in and out with the lively pop-pop of two-stroke engines under stress.
A sign proclaimed: "Irish Bar". Inside, one of a crowd of smiling girls asked over the loud music: "You wan' beer?" I spent a couple of minutes trying to get a Guinness. She had never heard of it - neither had any of her giggling associates. I settled for "beer".
I wasn't expecting it in a mainstream tourist bar, but after a couple of drinks I started to get offers: "Me come back your room?" I didn't ask about the price, but it would likely have been as cheap as the beer was.
Understanding that I was just here to take in the atmosphere, the girls went back to talking in Thai and broken English.
It was almost as if the offer had been made for form's sake; they were just a bunch of girls having fun, serving beer and joking with the customers.

3D JIGSAW PUZZLE
At 8 the next morning there were only a few restaurants open for breakfast and some hawkers setting out their wares. A couple of earlybird tourists were staking out their spot of beach with their towels. Some things never change.
By lunchtime the sand was packed with sun-worshippers in various stages of white, red and tanned. A new set of hawkers were at work on the beach. Food, cold drinks, ice cream, massages, hair beads, jetski and windsurfer rental - it was all there.
From hectic Patong Beach to the tranquillity of liveaboard boat life on mv Discovery - what a contrast! We had needed accommodation ashore before and after the trip but the waiting was over - we boarded that evening and headed for the Similan Islands.
Early next morning I could just make out shadows below the clouds to the east. The mountains of Phuket island rose about 50 miles away. The Similans are granite humps which rise from the clear, tropical sea. In some places, fissures in the granite have been etched and undermined to leave gigantic square boulders tumbled against the hillside and down into the water.
The granite is bare for the first few metres above the water; the area is swept by storms in the monsoon season. Then comes dense vegetation, as if someone had drawn a line on the rocks and ordered the jungle not to cross it.
Under water, seams and fissures have been eroded to leave a giant 3D jigsaw puzzle with poorly fitting pieces and some missing. Rounded blocks of granite lie propped together, with narrow chasms and triangular caves in-between.

ELEPHANT HEAD
I can only compare the Similan Islands to taking the best dives of Land's End and transplanting them to the Andaman Sea.
If you like good visibility and warm water, but are starting to find coral walls all blurring into one, the granite topography of this part of the world makes for a refreshingly different and beautiful place to dive.
Elephant Head is a typical, choice location. Above the surface, the smooth granite resembles the head of a swimming pachyderm. Below, some of the blocks are bigger than houses, with canyons through which you could fit a car.
Soft corals and gorgonians reach out from the overhanging sides, while shoals of fish swirl in the shade.
The boulders are on a slightly smaller scale at Christmas Reef, with its denser soft corals teeming with fearless fish. I have spent years stalking black and yellow-spotted clown triggerfish to get a good shot - here, one swam straight past me.

POPULAR OVERNIGHT
Nearby, and a fair bit deeper, is a small granite reef called Christmas Corner. Its smooth surfaces were covered in forests of huge gorgonians and soft corals. Tiny hard corals occupied the spaces in between these forests, but they had been unable to grow into a reef.
Donald Duck Bay is a popular overnight spot for dive boats. It is named after a granite boulder perched above the rocks.
Under water there is nothing special, but it makes a safe and easy night dive. Deep Six is a series of enormous granite steps and jumbled boulders at the north end of Similan island number 6, descending to more than 40m.
In addition to the usual gorgonian fans and soft coral, there are some nice black coral trees in the deeper water and lots of blue-spotted rays on the sand.

BOULDER CITY
Currents in many tropical locations are driven more by weather and season than tide, making it hard to predict just what will happen day to day. We arrived at Boulder City to find a ripping current, but with the promise of spectacular scenery and good visibility, we went for it anyway.
On the way down I could see smooth granite ridges stretching across the sand below, with enormous gorgonians paying homage to the current. As soon as I was sure that I could make it without getting swept clear, I released the line and headed for the shelter of the ridges.
I worked my way upcurrent, following ridges and back-eddies. Many fish seemed to be doing the same.
Ahead was a sandy patch with an eel garden. Sneaking up, I noticed a leopard shark resting on the sand. How could it take me so long to notice something that big?
I was almost in range for the shot I wanted when my over-enthusiastic buddy stormed in above me and spooked her. After a few minutes she started patrolling up and down a large sandy gully, seeking a place to rest. I stayed in the distance until sure she had settled, then approached carefully.
A trail of monofilament from her mouth indicated a narrow escape from a fisherman's line. Pausing between shots, I watched closely as the leopard shark watched me. It seemed that I had been accepted.
I moved back before swimming round to take her other profile. With only a few shots remaining, I crept up to the minimum focus of my camera. The lens was less than 30cm from her nose and still she did not flinch.
My film all gone, I just lay there being a leopard shark for a few minutes, before retiring to the line to make my safety stop.

swimming against the current at Boulder City

the scale of the rocks ashore gives some idea of the big picture under water


jumping in at Christmas Reef


leopard shark


royal angelfish


down in the galley

GETTING THERE Direct charter flights from UK to Phuket. Scheduled flights via Bangkok with Thai Airlines or via Singapore with Singapore Airlines. DIVING DETAILS:Mv Discovery is operated by Santana Diving (web www.santanaphuket.com). Be wary of local shops that are booking agents only, with no responsibility for the diving. It can be cheaper to do a course with equipment included than rent a regulator and BC. ACCOMMODATION: You need accommodation ashore either side of a liveaboard trip. A clean budget room with fan and bathroom costs about £20 in peak season.. MONEY:The baht, credit cards. FOR NON-DIVERS:Lots of cheap shopping, the usual watersports, theme parks, canoeing in Phang-Na National park, mountain-biking, elephant-trekking. BEST TIME TO GO:Between November and April, when the monsoon is on the Gulf of Siam side of Thailand and the Andaman Sea side is mostly calm. WATER TEMPERATURE:Take a 3mm suit or shortie and dive skin. DIVING SUITABLE FOR: Dives are deeper than at most tropical dive sites with moderate currents but newly qualified open-water divers seemed to cope. COST:Liveaboard diving about US $100 per day peak season, but many bargains to be found. Flights vary between £500-900, depending on time and route.

PROS: The Similans offer excellent marine life and a change of background from coral reefs. Low cost for overseas diving. Well-organised and diver friendly. Vibrant life ashore.

CONS: Fast day boats can reach many sites but the Similan Islands are best dived from a fast liveaboard boat. You need accommodation ashore either side of a liveaboard trip. Moderate currents.