In the wild the potential survival rate of the turtle hatchlings is one in a thousand but at the carefully monitored turtle project the survival rate last year was 93 per cent. The volunteers and staff move the eggs from the original turtle nest to a secure site and monitor them throughout the night. "The 2am-4am shift is the worst," says Mia, a volunteer from the United States. "But I still ask to be woken if they start to hatch, whatever the time."

When they are not on turtle watch the volunteers can turn their hand to surfing. Trying our luck, under the careful guidance of Eric we set out into the rolling Pacific with our boards. Despite spending most of the time submerged, we did all manage to stand up – after a fashion.

As Costa Rica is sandwiched between Honduras to the west and Panama to the east, with Nicaragua to the north, it is hard to avoid the Pan-American Highway that cuts across the country. Huge juggernauts, known as "18- wheelers" thunder along the highway but short distances off it take you to another life, where horses graze in every field, cattle with floppy ears are plentiful and spectacular scenery is worth the drive over potholed roads.

Having worked up an appetite in the waves, we headed to Playa Samara, a horseshoe bay with a selection of open-air restaurants on its flanks. Forgoing the staple of gallo pinto (rice and beans) and plantain, we devoured huge tasty prawns and near perfect piña coladas.

Leaving the south we drove to the rainforest in the northern zone towards the Tenorio Volcano National Park. The four-hour journey took us through lush and varied country – pineapple farms, sweeping succulent banana plantations and rich cattle country where the cows looked fat and happy and horses, usually shared by families as a means of transport, were everywhere.

By the time we reached the small town of Bijagua in the Upala region, we had left all traces of tourism behind and turning left by a small supply shop and restaurant, we headed up a dirt track, climbing to the eco-lodge of Las Heliconias.

Fortunately our trusty driver knew the way as there are no street signs in Costa Rica, not even in the capital San José. Ask a local for his address and it's along the lines of "turn right at the bank and it's on the left, opposite Soda Lucy".

It was dark by the time we arrived, but within no time we were off on a canopy tour, crunching tentatively over soggy leaves and squealing at vast spiders.

The lodge is owned by local Costa Ricans who opened the centre to promote sustainable development and ecotourism. More than 300 species of birds, including five different toucans, 18 types of hummingbird and the ornate hawk eagle, inhabit this rainforest area.

We saw the beady eyes of a kinkajou, a brown furry creature at the top of a tree, and a translucent frog the size of a finger nail among a flurry of creepy crawlies on our night stroll. And contrary to expectation, we were not woken at 4am by the howler monkeys.

The next day we saddled up and rode on some Criollo horses (native to South America) to the national park, taking in the view of Nicaragua Lake, the border being only about 20 miles away. A guided walk took us to the spectacular Rio Celeste waterfall, which cascaded majestically down a cliff through light cloud and mist before exploding into a pool of turquoise water.

Away from the noise of the water, we saw two different toucans, a chunky chap with a red chest and another with a colourful beak. When it comes to flora and fauna it is hard not to take pleasure in the rich biodiversity of this small country.

It is home to countless species of endangered birds, from macaws and humming- birds to woodpeckers and parrots. Its miles of coastline, mangroves and rain and cloud forest are so varied that even untrained spotters can enjoy the thrill of seeing rare breeds of bird and mammals, not to mention thousands of different plants and trees.

But you have to be on alert all the time. We would never have seen the sloth, so perfectly camouflaged among the higher branches of a tree were it not for the razor-sharp eyes of our guide.

The country is awash with national parks and private reserves, all providing well- signed hiking trails at ground level. Above the trees lies a network of suspension bridges and even zip wires through forest canopies and plunging waterfalls.

Costa Rica also has its fair share of mountains, with Mount Chirripo the highest at 12,530ft, and 121 volcanoes. The best known is Arenal, which is currently erupting in some style and at night can provide an open-ended firework display as red-hot molten lava explodes from the summit and tumbles down its flanks.

As a fitting finale we found a collection of cabins that looked directly onto the volcano. Had it been a clear night we could have sat out on our porch and watched as the volcano erupted. The area is also riddled with natural hot springs, the result of a chemical reaction between volcanic minerals such as sulphur and calcium carbonates. Our hotel had funnelled these springs into a series of pools of varied temperature, beginning with very hot and gradually cooling, with the final pool shaped around a bar.

But sadly it was not to be our night. As evening set in, so did the clouds, gravitating to the highest point of the volcano. They descended like a curtain, obliterating the star attraction that hung like a shadow, somewhere out in the darkness.