New growth in the forest

It's the third casualty of the day and we've been on the beach little more than an hour. It's not as if we haven't been warned. The signs say do not feed the monkeys and my guidebook warns of their propensity to open backpacks and raid picnics.

I have taken first guard, armed with a large stick but it's no match for the pint-sized thief, who pilfers a packet of lollies from my friend's bag within a minute of her slipping into the water.

Next to disappear is a container of Pringles. In a flurry of movement the snack is spirited into the branches, where a hairy arm disappears inside the tube, re-emerging with a fistful of potato chips that are gobbled down and showered onto the ground.

Manuel Antonio National Park, on Costa Rica's Pacific shore, is known as much for its stunning beaches as the white-faced capuchin monkeys who rule them. A quintessential rainforest-meets-beach location, it has become a pin-up park for ecotourism in a country that teetered on the brink of environmental annihilation, then transformed itself into a model of environmental protection.

Manuel Antonio is one of 160 protected parks and reserves in this small Central American nation, with more wilderness and wildlife for its size than any other country. About 5 per cent of the world's biodiversity is found in Costa Rica, though it is a quarter the size of Victoria. Twenty-five per cent of its land is protected - the highest national conservation rate on the planet - and the country's progressive environmental attitudes belie its Third World status.

Costa Rica forms part of the Central American umbilical cord, wedged between Panama in the south and Nicaragua to the north, with miles of ocean frontage on the Pacific and Caribbean coasts. With a sticky climate and drenching tropical rain, the country is spectacularly green; a tapestry of cloud and rainforests, waterfalls and volcanoes, with a mountainous interior and jungles that dissolve into white-sand beaches and emerald lagoons.

It hasn't always been this way. In the latter half of last century, much of Costa Rica was cleared for agriculture, diminishing forest cover by 80 per cent. The extinction of the iconic golden toad in the 1980s and a growing awareness of climate change, however, helped trigger a massive program of reforestation. Aided by a $US26 million "debt for nature" swap with the US in 2007 and a scheme that pays land owners to preserve the natural environment, forest now covers more than half of the country.

Eco-tourism has overtaken coffee and banana production as the nation's primary revenue source and Costa Rica is aiming to be the first carbon-neutral country in the world by 2021. In 20 years, the country has been transformed from one of the most deforested in Central America to a pioneering environmental performer.

At Manual Antonio National Park, Josue Rosales is among a new generation of eco-warriors. His grandfather was a shaman, or medicine man, and when he died Rosales inherited not only his love of nature but a 53-hectare property he is conserving as a private nature reserve. When he is not guiding visitors through the park, Rosales is working on plans for sustainable tourism projects at his reserve, which he hopes will provide jobs for young people and perpetuate the conservation movement.

Manuel Antonio was declared a national park in 1972 and is one of Costa Rica's smallest but most visited nature reserves.

Its 2000 hectares comprise primary and secondary rainforest, mangrove swamp and dramatic horseshoe bays that spill into dolphin- and whale-watching waters. Inside this compact sanctuary are 109 species of mammals, including the endangered squirrel monkey, 352 kinds of birds and 346 types of plants.

When I meet Rosales, he's wearing an outdoor vest with more pockets than purpose, and has a telescope slung over his shoulder. Months away from completing a masters in biology, he has an encyclopedic knowledge of flora and fauna and a repertoire of animal calls he uses to charm the wildlife from the trees.

Three of us follow Rosales like the Pied Piper, traversing a path through a curtain of towering trees and twisted vines. There is a rustling in the branches and soon we're joined by a family of capuchin monkeys. They thrash about in the trees, shovelling berries into their mouths, and cannon-ball across the forest as though propelled by spring-loaded limbs.

Rosales finds a tiny pair of bats, each the size of a toddler's fist, dangling under a palm leaf. Tangles of spiderwebs line the path and the forest floor moves with hermit crabs and skittish Jesus Christ lizards, so named for their ability to run on water.

At the rangers' station Rosales spies a pair of three-toed sloths camouflaged high in the trees. One is on the move - a rare sight for a creature that sleeps 17 hours a day and leaves the boudoir only once a week to visit the bathroom. It looks like a big teddy bear, with a grey wiry-looking coat, round piggy nose, long curled nails and elongated arms that move in slow, tai-chi motions. "They are like public service workers in Costa Rica," Rosales quips.

At the station, we each collect a sapling to plant. They are left over from Arbor Day, a national tree-planting day, and I'm thrilled to be part of the revegetation effort. With some inspiration from Rosales I name my tree Gaia, meaning mother earth, and find a shady home for it while a green iguana watches from a nearby tree.

Not far from our newly planted saplings is a carpet of blinding white sand folded into a shimmering lagoon. We have reached Playa Manuel Antonio, a palm-fringed beach made famous in the film Jurassic Park. It's not surprising really, given the prehistoric critters we have encountered. It's early morning and we have beaten the tourist hordes. The beach is serene and all ours. And then the monkeys descend.

When there is no food left to pillage, we swim and snooze carefree. Hours disappear and so does Rosales. At the western end of the beach we explore Cathedral Point, a rocky headland jutting into the Pacific. The point was once an island and, at low tide, a semi-circle of rocks can be seen that is believed to have served as a turtle trap for pre-Columbian Indians. A steep path leads to a lookout with views across the ocean and islets, then on to yet another white-sand beach, Playa Espadilla Sur.

Manuel Antonio is a photographer's delight but is not as pristine as the postcards suggest. On the return circuit to the entrance we have to splash through a shallow estuary, where signs warn that the water is contaminated with human waste. This and the habits of the monkeys, which have been spoiled by irresponsible tourism, are a reminder of the delicate balance between progress and preservation and the fact that, despite often contrary appearances, Costa Rica is still a developing nation.

That said, it has made progress on social and environmental issues that many First World nations could follow. The nation elected its first female president this year; it has an enviable national healthcare scheme, an unemployment rate of about 6.5 per cent and a free and compulsory education system that delivers a literacy rate of 97 per cent.

There is no standing army and the former president, Oscar Arias, won a Nobel Peace Prize for his efforts to end the civil wars that raged across Central America in the 1980s.

Most of the population of 4.5 million Costa Ricans, or Ticos, enjoy a good standard of living. A church, soccer field, school and bar are staples of any town and the ubiquitous "pura vida" spirit, meaning pure life, is infused in their culture.

In the three weeks I have to find my own pura vida I hurtle over the Monteverde Cloud Forest on a zip-line, stare into the boiling belly of Poas Volcano and swim in the pristine waters of La Fortuna Waterfall, in the central highlands. On the Caribbean coast I sweat buckets in the laid-back reggae village of Puerto Viejo.

I snorkel and cycle to sleepy Manzanillo Beach near the Panama border. Further north I crouch within catching distance of a majestic green turtle as she lays her eggs into a sand cradle on one of Tortuguero's remote beaches.

I leave knowing that, in all likelihood, this is one country destined to be even better when I return.

Getting there

The easiest and cheapest way to get to Costa Rica is via Los Angeles. Qantas has a fare for about $3070 low-season return from Melbourne and Sydney including tax. This involves flying to Los Angeles (about 15hr), then an American Airlines flight to San Jose via Dallas (about 8hr 30min including transit time). Australians must apply for US travel authorisation before departure, costing $14, at https://esta.cbp.dhs.gov. It is also possible to fly via South America, either through Santiago, in Chile, or Buenos Aires, in Argentina.

The port city of Quepos is the gateway to Manuel Antonio National Park, located about 130 kilometres south of San Jose. Regular buses and private transport are available for the four-hour journey to Quepos. Charter flights on Nature Air from San Jose to Quepos cost about $US130 ($128) return.The entrance to the park is about seven kilometres from Quepos and the route is serviced by taxis and cheap public buses.

Walking there

Manuel Antonio National Park is open 7am-4pm, Tue-Sun. Entrance costs $US10. Group walking tours can be organised or pack a picnic and go alone. If visiting independently you can hire a guide at the entrance and afterwards explore the park and relax on the beach.

Accredited guides are available at the entrance for $US20 a person. A guide is highly recommended to maximise wildlife viewing opportunities.

The main walking circuit is about two kilometres and cuts through the forest to the most popular beach, Playa Manuel Antonio, and then back along Playa Espadilla Sur.

Staying there

Hotel Makanda by the Sea, halfway between Quepos and Manuel Antonio National Park, has six villas and five studios, all high in the rainforest and with views across the Pacific. Rooms from $US200 a night (low season); see makanda.com.

Hotel Mono Azul is a more modest option, convenient to the national park. Rooms from $US45 a night; see hotelmonoazul.com.

Touring there

Gap Adventures has nine-day budget tours of Costa Rica, visiting San Jose, La Fortuna and Arenal Volcano, the Monteverde Cloud forest, Quepos and Manuel Antonio National Park, from $899 a person (excluding airfares); see gapadventures.com.