Being surrounded by young people, all generating that collective sense of excitement that comes with trying something new, brought back to me the feelings I had when I started diving some 17 years ago.

As I stepped off the Lomprayah high-speed catamaran from Koh Samui onto the rickety jetty on the island of Koh Tao, my senses were immediately overwhelmed by the sound of bar music, the smell of cooking food and the throngs of young travellers.

Between potholes filled with rainwater, trucks and mopeds fought for the few remaining square metres of dirt track that led up to the jetty. Within a few steps strangers were offering to take care of my diving needs for the duration of my stay. This was backpacker heaven.

I was booked into the Big Blue Diving Centre which, on first impressions, seemed well-enough organised. I was shown to an air-conditioned room with a bathroom attached, just a few metres from the beach and dive centre.

The various dive centres have their respective bars lined up along the shore. Oddly, they don't seem to compete with each other but simply co-exist, like various branding exercises for cool.
My first surprise was that the barman at our dive centre turned out to be the son of a good friend back in England. Even stranger, it turned out that Joe would also be my dive guide for part of my stay.

It was towards the end of the June-October low season during which the weather in the Gulf of Thailand can be changeable to say the least, but the tourist authorities are naturally keen to promote year-round diving. Are you a gambler?

As it turned out, the weather would remain superb throughout my stay. The sea took on an eerie flat-calm quality which I had never experienced before and the sun shone ferociously. If you do take a chance and visit Koh Tao in the low season, you'll find that prices in an already cheap place are even cheaper. It's also less crowded.

Long-tails, which are wooden constructions powered by huge outboards, whiz you out to one of the large dayboats that take you on to your dive site. These boats are not pretty but they are well-maintained, functional and in my case seemed to house the local skipper's family too.

Chumphorn Pinnacle and White Rock to the west of Koh Tao provide a series of underwater rock formations and swim-throughs guarded by shoals of barracuda. This is a popular place and much used for the training of novices. However, squadrons of divers swimming in close formation were not an exciting enough spectacle to create a good first impression.

South-west Pinnacle, in fact a series of 25 pinnacles, was more successful in grabbing my attention. Vast arrays of anemones clung to the rock while their faithful clownfish weaved in and out of their tentacles. Damselfish in their tens of thousands hugged the sides and titan triggerfish guarded their nests from photographers who ventured too close.

Below, football fields of sea urchins, arrayed with mathematical precision, gave immense scale to the scene.

Chumphorn Pinnacle was to figure repeatedly in the next few days as reported sightings of whale sharks increased. It was my sworn intention to photograph such a beast and that was exactly what I tried to do - along, it seemed, with half the population of the island. But my usual bad luck was to prevail and I came back empty-handed.

Perhaps you will be luckier than me if you go to Koh Tao. They certainly talk a good whale shark there - the resort staff discussed their experiences more frequently than at any other location I have ever visited.

Hin Kao, or White Rock, to the west of Koh Tao, has some lovely swim-throughs with abundant soft corals at the base interspersed with sea fans. The mighty triggerfish dominated here and I saw a couple of moray eels. The seascape was impressive but the visibility was not always a match for it, a problem which cropped up from time to time as a pot-luck feature of diving outside the main season.

To the south-east of Koh Tao is Shark Island, named, rather disappointingly, because of the shape of a shark fin formed by the top of the island itself.

I say disappointingly because I didn't see any sharks there. This is a shallow dive on sloping rocks from 5-20m decorated with loads of soft corals, sea fans and barrel sponges. My old friends the titan triggerfish were there too, trying to relieve me of a few ounces of flesh, and poor visibility and too many divers put a bit of a further damper on proceedings.

But I liked the relaxed approach to diving in Koh Tao. Instructors coached their pupils in the open-air bar as young novices came and went from the water. Safe diving practices appeared to be suitably emphasised and everybody seemed to wear a happy smile. Even I adopted one after a while.

Koh Tao is usefully placed for anyone heading on to Australia, as you can get yourself qualified before you get there. This is common practice for a lot of travellers who arrive with no equipment and can rent all they need for the course they want. For example, a four-day standard Open Water course, including four nights' accommodation, costs only about£150.

For me Koh Tao is a place for young backpackers low on money and high on adventure. It is what it is, and perhaps what I like about it is that it doesn't pretend to be anything else.

At the time of writing and in the wake of the Bali bombing, the Foreign Office is discouraging British tourists from travelling to Thailand and Indonesia. Divers must decide on what they consider constitutes an acceptable risk.

Diver surveys the scene at South-west Pinnacle

what Koh Tao is all about - young people having fun

below the boat, urchins stake their claims at South-west Pinnacle


GETTING THERE:Zac Macaulay flew with Thai Air to Bangkok and on to Koh Samui, followed by a boat crossing to Koh Tao.
DIVING AND ACCOMMODATION: Big Blue Diving (0066 77456050, www.bigbluediving.com) is a PADI five-star centre and was one of the first dive shops to open on Koh Tao
WHEN TO GO: Dive centres are open all year round, though you are taking a big chance on the weather if you come here during the monsoon season between June and September. For the budget-conscious, however, the diving is even cheaper at this time. Temperatures ranges from 30-40°C.
MONEY: Thai baht, major credit cards.
FOR NON DIVERS: Snorkelling, hanging out.
COST: Return flights to Bangkok cost around £450 and onward transfers £90. Cheaper train/boat transfers are also possible. Backpacker-style lodgings start at £4 a night, diving from £14 a day. For more stylish tailored travel, try Symbiosis Expedition Planning (0845 123 2844, www.symbiosis-travel.com).