A scientific research project in Western Australia offers the chance to explore the coastline by day and track turtles at night.

Glenn McFarlane looked bone weary. "Any luck tonight?" I ventured timidly. "No, no turtles," he replied. Though frustrated, he mustered a half smile and looked for the silver lining. "Just a lovely walk on the beach with good company and good conversation. Now I have a date with my pillow."

Glenn was expedition leader for a two-week volunteer beach patrol programme gathering data on the Australian flatback turtle. In our briefing earlier that day, he'd explained that of the seven species of sea turtle, six are classified as either endangered or critically endangered. But not the flatback. Up on the screen in Glenn's presentation we'd read the tantalising words – "data deficient"; it's why we, and Biosphere Expeditions, were at the southern end of Roebuck Bay in Western Australia.

The far north-west of Western Australia is one of the country's most captivating regions, taking in the vast Kimberley outback and coastline. The barely fathomable expanse of blood-red desert floor is carpeted with wattles and eucalypts – a unique landscape known as "pindan" in the local Aboriginal language. Near the coast, the desert lightens from red to ochre, shot through with bright orange ribbons of dust which take the form of roads. Then, without warning, the sand collides with the sea, the blinding turquoise of the Indian Ocean splashed against a palette of red earth, sandstone cliffs and bone-white beaches.

The muggy 35C days I was experiencing were a harbinger of the tropics wet season that runs from December to March. Peak time for tourists, however, is the dry season from June to September, when temperatures are a steady 28 to 33C and there is scarcely a cloud in the sky.

As Glenn trudged off to bed, I shouldered the backpack loaded with gear we needed for "processing" a turtle, and our group of three, including patrol leader Wren McLean, hit the beach.

Most nights during the November-December nesting season a number of female flatbacks crawl out of the ocean, dig holes in the sand and deposit about 50 eggs. The breeding cycle (which begins at around 22 years old) will bring them back to nest every two to four years, on the same beach where they themselves were hatched. Male turtles never make landfall.

Our brief was simple enough and Wren had done plenty of turtle patrols, but I was feeling decidedly nervous about my first encounter with a nesting flatback. During his presentation, Glenn had made it clear he would not tolerate mistakes, not even from first-timers. Measurements were to be triple-checked, a precise egg-count taken (as the turtle is laying them), and details from old tags recorded. For any untagged turtles, new tags had to be attached and a tiny flesh sample snipped for DNA analysis. Though it was a balmy tropical night and the sky was festooned with stars, fellow volunteers Katherine and Jade and I were quietly tense as we fell in behind Wren and began marching at purposeful pace along the water's edge.

At least as intriguing as the lives of the turtles are those of the people moved to contribute to their conservation, whether as project volunteers or as a way of life. Katherine was a Californian, recently retired from her job with Nasa's Life Science projects. Jade was a 24-year-old Tuscarora Native American from New York State; she was also a former US Marine now plying her trade as a satellite communications expert for a private firm in Afghanistan.

I was mightily pleased they were on my team, because besides "processing" turtles, we were expected to map their nest sites using a GPS gizmo that I wasn't sure I could use with any confidence. I would do my best to wrangle a turtle, measure it and count its eggs, but when it came to deploying global positioning technology, I was glad to have Nasa and the US Marines on my side.

During the next three hours we trekked north roughly two miles along the firm damp sand, then turned and retraced our steps. There wasn't so much as a flipper track to be seen, but the temperature was 27C and the beach a silent moonlit wonder. Biosphere makes clear that volunteers need to expect legwork with no guarantee of animal encounters. I wasn't disappointed by the experience: it's not often I find myself on a remote beach after midnight. While we were patrolling, Wren gave us some additional insight into turtle behaviour, and perhaps that of our somewhat grumpy expedition leader.

"Glenn's come straight from a flatback project in the Northern Territory. They lived in an unshaded campsite for more than two weeks, doing beach patrols at night and trying to sleep in staggering heat during the day." This struck me as a measure of what people who care passionately about an animal species will do to protect it.

By contrast, our living situation, at Eco Beach Retreat, could hardly have been more amenable. The spacious tents are set on wooden platforms and have proper beds, tables and electric fans; villas are air-conditioned and most have ocean-view decks. Besides the beach, daytime recreation options included a pool and bar, fishing, sea-kayaking, birdwatching and yoga.

Kurt Williams (an Aboriginal from Derby, one of the gateway towns to the Kimberley outback) runs boat- and land-based fishing trips from Eco Beach. I met up with him and two other resort guests for a foray to Jack's Creek, a six-mile drive north along the beach. The mid-morning temperature was a withering 36C. On the river bank there was nowhere to hide from the sun, but the prospect of landing a barramundi or mangrove jack – prized table fish in any Australian restaurant – kept us all focused. In the course of three hours' fishing, everyone else bagged a mangrove jack while I kept throwing back catfish, even as we developed fast friendships in the way blokes standing on a river bank do.

Having hit it off with Kurt, I was pleased to discover he was up for guiding a morning kayaking expedition the next day along the coast. A stiff onshore wind had made the water choppy and there was a small swell running. So Jade, Kurt, Tyler (an American high school maths teacher and turtle volunteer) and I had some fun with the waves as we paddled past stunning coastal caverns and a precariously leaning rock pillar adorned by an osprey nest.

When we pulled in at a sheltered beach for a swim, the water was an extraordinary 32C, slightly warmer than the air temperature. For half an hour we floated about, goggling at the stunning rock formations and blood-red cliffs and laughing about my tragicomic fishing exploits.

Back at base, the entire turtle team – eight volunteers and three patrol leaders – assembled for lunch followed by a detailed presentation from Glenn about the status of sea turtle populations and the main threats to their survival.

Illegal trade in "tortoiseshell" (fashioned into decorative objects) and sex organs (dried, powdered and sold as an aphrodisiac) are among a depressing litany of human predations, together with the poaching of eggs and drowning by fishing net. It was impressed upon us that the data we collected would contribute directly to the understanding and conservation of flatback turtles, a species that is so far known to nest only on Australian beaches.

My first two nights on patrol had been conspicuously turtle-free. But as is the way with observing animals in the wild, nothing much happens until it does. An hour before the early patrol was due to head out, Glenn's walkie-talkie crackled into life; Kurt, Wren, Jade and Tyler, on their way back from fishing at Jack's Creek, had detained a turtle that had come onshore well before sunset.

That night our team was due to harness one turtle with a satellite antenna pack. Local journalists and a television crew were mustering to cover the rare event. It was well before dark and the media was not yet on site, but this might be the only turtle we discovered that day, so a decision was made to harness it and take the photos ourselves. Glenn darted off to retrieve the antenna unit while the rest of us sprang into action, grabbing turtle processing packs and cameras.

When the Biosphere vehicle careened to a halt beside Kurt's 4x4, we found Tyler leaning on the front of the turtle's shell, preventing her from moving towards the water. Glenn and fellow "turtle guy" Tony donned surgical gloves. While Tony relieved Tyler as turtle-wrangler, Glenn barked out instructions for lifting the animal onto a square plastic box. As soon as it was measured and its tag details recorded, Glenn slipped the harness on, then tightened it before slicing off the ends of the straps. Anyone not occupied with measuring, scribbling notes or punching in GPS co-ordinates was snapping photos, making sure we captured the frenzied activity. At last the patient mother-to-be was gently lifted back onto the sand. Having checked the antenna was transmitting, Tony cleared the way for her to return to the sea.

The final diary entry on the Biosphere website summed up the sense of fulfilment. "The high tides and full moon this week gave us some fortunate chances to view and photograph turtles in the light... All team members had intimate and memorable moments with our ancient turtle friends and most witnessed the nesting process. Most of the turtles we encountered have been re-migrants, meaning they have already been tagged whilst nesting over the previous two years of the project. Good vibes all round as Team Two waved goodbye this morning..."

Travel essentials: Western Australia

Getting there

* The nearest airport is Broome; Qantas (08457 747 767; qantas.com) flies from Heathrow via Singapore and Perth. Returns start at £1,100, for travel from 11 Aug–30 Nov.

Visiting there

* The eight-day turtle monitoring experience is run every November by Biosphere Expeditions (0870 446 0801; biosphere-expeditions.org). Prices from £1,370 per person, including accommodation, transfers, breakfast and dinner daily, turtle research activities and training. Book well in advance. Minimum age 16.

Staying there

* Cable Beach Club Resort, Broome (00 61 8919 20400; cablebeachclub.com). Studios start at A$297 (£196), room only.

* Eco Beach (00 61 8 9193 8015; www.ecobeach.com). Eco Tents from A$165 (£109), room only.

More information

* westernaustralia.com