The sign that greeted me at the airport read: Dank U Wel, in Namen de Ezels - Thanks on behalf of the donkeys, all donations gratefully received. By this late hour I had reached the 90m-narcosis stage of jet lag, and staggered into a taxi, wondering what sort of island economy got itself held to ransom by donkeys.

The flight had been a marathon session of Dutch-colonial hopscotch: Amsterdam, Oranjestadt and Willemstad, till finally Kralendijk crept over the horizon. A long way to go, and I needed this holiday to be good. It was to prove a distinctly strange place, but as soon as I reached the hotel, I knew I had chosen well.

I was staying at Captain Dons Habitat on Bonaire, in the Dutch Antilles. Its boats go out three times a day for one-tank dives, travel times being short. There is also unlimited free shore-diving, so a determined diver can easily do five or six a day. I took it easy.

The entire leeward side of Bonaire and its little buddy Klein Bonaire is a coral drop-off, with a slight current parallel to shore. So the typical plan is to descend to 20m, fin upstream a while, rise to 12m, drift back, then laze around beneath the boat for a final five minutes.

Coral is the principal attraction, fantastically encrusted like a vista of Toon Town. Fish lie low till dusk, when they all promenade: the big-eyed scad form sinuous, silvery zeppelins, and traffic lanes of blue tang stream home from their day at the office.

The dive guides were excellent, searching out interesting beasties (the frogfish a malignant tangerine, the seahorse bizarre yet demure), but otherwise letting us alone: no tank-tinking or hurrying us along. If there was already a boat at one dive site, we just motored for a couple of minutes to the next.

Much of the coast is a marine park: dont touch, dont remove, and dont drop anchor - all the sites are buoyed. The shallow coral was damaged by Hurricane Lenny two years ago, but this is mainly a disappointment for snorkellers, and even they will still find plenty of coral, especially round Klein. Below 10m, it is mostly intact.

Non-diving attractions are few but shouldnt be neglected. Choose between windsurfing or nudism at Sorobon, and the charms of downtown Kralendijk are worth 20 minutes, putting it ahead of many famous seaports. The island scenery is arid and haunting.

The south end is an aching expanse of shingle, driftwood, mangrove scrubs, salt-pans turning through lilac and lavender to icing sugar, old slave huts no bigger than hen-coops, and flamingos fastidiously picking through the silt. I halted my sit-up-and-beg Dutch bicycle to rest from the incessant wind and photograph the donkeys: what can they eat out here They seemed to be eyeing the bicycle.

North end is Washington Slagbaai National Park, a day trip in a 4x4. I followed the dirt road for 15 miles past bristling stands of candle cactus, brackish pools, more donkeys and windward cays where the surf raged and sucked. Every stop became a Jurassic car park, as hundreds of blue-whip lizards converged, rustling, in hope of titbits.

The landscape was like nothing on Earth. This could be early summer on Mars, when the melting ice cap feeds ephemeral pools, green tuberous things and hee-hawing beasts (Ive never been, but Great Aunt Vreni was always harking on about the Old Country). Something else was weird about the island, but I couldnt put my finger on it.

Meanwhile, the diving was making me chilly. Chilling out is all very well, but Id come to escape a protracted British winter. How come shacks in warm countries can hire you only shortie suits, even though you point out that the dive-leaders prefer something stouter I bought myself an ONeill 3mm longjohn, and felt much better.

It was a hotter morning when, on the ride out to the dive site, a boat exploded ahead of us. We hove to beside an ugly mass of polystyrene blazing at the waterline, and a litter of timber and trash. Word was that the skipper had already been rescued, and we saw no bodies on the surface. Our group did not have the skills to mount an impromptu underwater search, and I resolved to practise those skills back home in Britain: you never know when therell be a next time.

So that was another tale for drinks and dinner back on the hotel terrace, as we looked for the elusive green flash at sunset (more like a sliver of unripe banana) and watched the night divers lights. At dusk, a moray prowls the jetty steps, preying on orange-kneed crabs, and two large tarpon, Charlie and Charlene, patrol the shallows.

Old salts like the original Captain Don sometimes come by, with yarns of schooners, storms and pioneer days of diving. Its as if the Beach Boys grew up into Grandpa Simpson, and after my fourth slug of Chardonnay I would slide the same way, anxious to tell my table of American corporate high-fliers about the remarkable stickleback Id seen on my last UK dive.

Muddled dreams - then, at 3am in my sleep, it hit me what was strange about the island. Kerrist! Where were all the children Had the donkeys got them

They were mostly away on the mainland, I later learnt, and those in school locally didnt bunk off. Not much point on a desert island. Not much cover.

Saturday morning was the best dive yet, on Bonaventure off Klein. We found a lobster, a moray, and the finale was a green turtle. The three-minute safety stop became 13 as we followed its leisurely, grazing progress over bright sands and clusters of feathers, fans and whips. It was a good point at which to finish, especially as my first stage now blew out, with a shriek like a mortally wounded set of bagpipes.
That looked like the end of the underwater adventures, but I took myself snorkelling by the hotel, using a mooring line to get down to 6m for a closer look. The scad, which locals call maspango, were in particularly fine form, in a dense silvery mass.

After a minute or so I needed air, but couldnt resist getting closer. A guideline ran along the seabed and over the drop-off, and I hauled myself deeper. The scad formed a little arch to let me through.

It was too deep, too far and too late in the day, and I'd have looked stupid getting a bend on a shallow breath-hold; but for a glorious moment I was whirling within a shimmering tunnel of fish.

Divernet
The
The jetty at Captain Dons Habitat
diver
diver and orange sponge
Diver
Diver framed by colourful reef formations
giant
giant tube sponges

FACTFILE

GETTING THERE: Fly KLM via Amsterdam and neighbouring island Curacao, or head for Miami or Atlanta and connect through Air ALM.
DIVING AND ACCOMMODATION: Captain Dons Habitat is a PADI five-star centre and caters for nitrox and rebreather diving, 00 599 717 8290, www.habitatdiveresorts.com.
WHEN TO GO: Bonaire is south of the hurricane belt, hot (average 28°C) and dry, so diveable all year round.
WATER TEMPERATURE: 25-27°C.
MONEY: US $ and credit cards. You seldom see an Antilles florin.
DIVING SUITABLE FOR: All standards, with plenty of easy dives for beginners.
COST: Graham Sands paid £1268 for eight nights at Captain Dons Habitat, including B&B, flight with KLM, five boat dives and unlimited shore dives, through The Barefoot Traveller, 020 8741 4319, www.barefoot-traveller.com. For other booking options refer to the ad pages.
FURTHER INFORMATION: Bonaire Tourism Authority, 00 59 97 8322, www.interknowledge.com/bonaire