Taking a deep breath from my oxygen mix, I check my gauges. I readjust my mask and tip backwards, watching as clouds and blue sky fill my vision.
There's a second of free fall before my back hits the green-blue, warm tropical waters. Bubbles spill all around while I right myself and signal the OK to the dive master still onboard the boat. My location? Latitude 4° 7'38.95"N, longitude 118°38'11.32"E. I'm floating effortlessly on the Celebes Sea off the coast of Borneo in Malaysia's most eastern state. Sipadan Island, where some 3,000 species of fish and hundreds of coral colonies have flourished, is considered by many to be the ultimate in diving.
As I head below the waves and approach the edge of the reef, I catch a glimpse of movement on the edge of my field of vision. Slowly finning, I turn and suddenly find myself face to face with a giant green turtle. It glides effortlessly through the 27° Celsius water while keeping a weary eye on this newcomer. I slowly lose the turtle's outline as it fades into the blue and I find myself staring into the void. It's day one of a five-day dive trip to one of the most pristine diving destinations in the world. And my heart is racing.
"You can dive your whole life and never see the abundance of marine life in such a small area as you do around Palau Sipadan," I'm assured by our host, Clement Lee, from Borneo Divers, the first dive operator to open up the destination to the world back in 1984.
Lee tells me: "Twenty-seven years ago when we started doing dives, we had a 40hp engine in a small dingy and from Semporna we'd take more than four hours to get to the island. When I talk about it the younger generation looks at me strangely. How is it possible? Now we have 400hp on each boat - it takes us less than 30 minutes. Talk about a GPS or compass. We didn't have luxuries like that. We had to find our way to the island. If it rained or if it was cloudy you couldn't see anything.
"From the first moment we put our heads in the water we knew this island was our future," he says.
The uniqueness of Sipadan and the surrounding islands lies in its maintained biodiversity, something I come to witness first-hand in the days to follow. Here, it's possible to see everything on a single dive, from the smallest crustaceans - some measuring less than half a centimetre across - to fully grown, 2m-long, white-tip reef sharks. Dipping below the waves, I encounter schools of fusiliers, beautiful batfish, giant cuttlefish, eels, stingrays, frogfish and brightly coloured nudibranches.
This paradise island, originally formed by living corals that grew on top of an extinct volcanic cone, rises 600m from the ocean floor of the Indo-Pacific basin. The oval-shaped reef that surrounds the island offers a variety of dive sites, each with its own unique sights: Coral Garden, a sloped coral wall teeming with brightly coloured fish; the Drop Off, a vertical abyss that descends into the depths and offers a dive profile of 30m of sea life variety for the recreational diver; or Turtle Cavern, aptly named for the dozens of turtles seen resting in the volcanic crevices that punctuate the underwater slopes. And with others such as Lobster Lair, Mid-reef, Southpoint, Staghorn Crest, Turtle Tomb and White-tip Avenue, your choice of site can sometimes be a hard one.
With an average water visibility of about 20m - something I've seldom experienced in the 60-plus dives I've done so far - it is easy to spot marine life. Using the current, experienced and novice divers alike can easily drift along the vertical walls, slowly passing from one oceanic creature to another.
At one of the most popular sites, Barracuda Point, I find myself surrounded by a massive school of jackfish numbering in the hundreds, their glistening silver bodies closing in around me in a mesmerising cloud. Bunching together, the shoal seeks survival in numbers from the white-tip reef sharks milling about on the outskirts of the school. I watch as one leisurely works its way closer to the shoal, looking for strays to catch unaware. As this scene unfolds I'm reminded of Jacques Cousteau's famous words: "I have seen other places like Sipadan … 45 years ago. Now we have found again an untouched piece of art."
The story goes that Cousteau's famous research boat, the Calypso, strayed into Malaysian waters while working on a documentary on sperm whales. While the matter was being resolved, the crew decided to dive around the island. They were instantly awed by what they discovered. Cousteau, who was not on board at the time but, in fact, having lunch with US president Ronald Reagan, was promptly called and convinced to board the first available flight to come and see it for himself. After diving the reefs of Sipadan he immediately commissioned a documentary. When Borneo: The Ghost of the Sea Turtle was released in 1989, it brought international attention to Sipadan.
But with the acclaim came visitors in their tens of thousands - and an element of risk. The island's somewhat precarious location, in close proximity to the Philippines, has proved troublesome in the past when it was the scene of a hostage drama in April 2000. The Filipino Islamist terrorist group Abu Sayyaf kidnapped 21 people, forcing 10 tourists and 11 employees onto their vessels at gunpoint and taking them to Jolo in the southwest Philippines. Fortunately, all the victims were released unharmed albeit after several months in captivity. The UK Foreign and Commonwealth Office website currently contains warnings that isolated parts of Sabah such as Sipadan and Mabul might be subject to future terrorist attacks or piracy.
Keen to preserve paradise, park rangers now strictly control entry, checking dive permits at the island jetty. Only 120 permits are issued each day, each costing 40 Malaysian ringgit (Dh50) and giving divers access to the reefs from 6am until 6pm. This gives the habitat and its aquatic life some nocturnal respite from the daily throng of inquisitive bubble-makers. It's also been the main reason for the quick recovery of the natural resources; the purpose-built accommodation for tourists on Sipadan itself has been closed. Today divers stay within speedboat distance at resorts including Borneo Divers on Mabul Island.
"When the Malaysian government declared the island a marine reserve in 2004 and we were asked to vacate, we took the bull by the horns and decided to be the first to leave. Bit by bit, we moved our entire operation to the neighbouring Mabul Island. I knew it was something we had to do. At that time the environmental impact of so many visitors had already become evident. We had to do it for the island. There were simply too many people," says Lee.
However as my dive computer signals 50-minutes dive time and I check my air supply, I find little evidence of any of this at the sites around me. I leisurely ascend the reef wall of the famous Drop Off and watch the 600m abyss fall away beneath me and give rise to the shallow reefs that surround the island. As the usually tedious seconds count down on my mandatory safety stop at a depth of 5m, I am instead entranced by the vibrant display of clown fish and brightly hued reef fish darting from side to side in the current while sticking close to massive tree corals.
As I'm about to break to the surface, I spot a school of giant bumphead parrotfish meandering through the coral reef; I can hear them biting at the coral. Their impressive hulks fill the water and cast shadows in the low tidal bottom. As I watch them pass I find myself reluctant to leave behind this entrancing destination. I hear the dive boat approach and I know it's time to go, but in my mind I can't help but fantasise about the day I will return.