Island-Sity

That I was wandering alone in a derelict part of Beira was my own fault. I had foggy memories of the city being a glamorous, Portuguese-run seaside resort where, in the Seventies, our family had driven in our VW Beetle from our Zimbabwean home for two weeks of searing sun on the palm-lined beach.

But that was before the wars: the war of independence that drove out its Portuguese colonisers, and the subsequent civil war that killed 100,000 Mozambicans. When I arrived again in 2009, it was with the hope that Beira might have been resuscitated in a similar way to Maputo, the Mozambican capital, where I had been a year earlier: vibrant with jazz clubs, colonial houses converted to b&bs and lively local markets.

It hadn't. It was like a scene from the film Blood Diamond. Potholes, some the depth of buckets, dotted the roads, some filled with plastic bags, rotting vegetable matter, castaway cans. Single-room shacks amassed from whatever cast-offs its inhabitants could find lined the roadsides. Iron bars replaced bombed-out glass in the windows of concrete high-rise flats. And once-grand buildings – now barely standing amalgamations of broken pipes, exposed electrical wires, rusted metal stairwells and holes – lined every street.

After walking through a market, I wandered back to my hotel and texted my partner. "We think our economy in UK is dire. But no comparison to here. Scarily poor. Been told not safe for woman on own so back in hotel room with broken fridge, clattering air-con and nylon sheets. And they call this three-star…"

Sitting a few days later outside my own spacious beach chalet at Nuarro eco lodge in northern Mozambique, with views over creamy sand and a pale turquoise lagoon, it was hard to believe I was in the same country. At my feet, birds chirruped in the greenery. A fellow guest in a bikini waved from a dhow, sundowner in hand. In the distance I saw Trienke, one of Nuarro's owners, walking her dog on the beach. It was like the Maldives without the Disneyfication, like Mauritius without the five-star razzmatazz. It was pretty darn perfect, as tropical scenes go.

Although Mozambique is one of the poorest nations on Earth, it has fantastical natural assets: a 1,500-mile coastline, rich with coral and marine life; thick hardwood forests (or at least vestiges of them, given the rate at which China is destroying them); game reserves half the size of Wales; and warm seas through which humpback whales migrate.

Since the government changed legislation to make it possible for foreigners to acquire 50-year leases on land, there have been increasing numbers of lodges, b&bs, campsites and holiday homes built. In 2005, more than 575,000 tourists visited Mozambique, the 37 per cent annual increase making the country's tourism industry the fastest growing in the world.

When Lola Carnero, a Brazilian, and her British boyfriend, Steve Hodges, arrived in 2005, she says they had heard that the country "had amazing dives, amazing beaches, beautiful people – so we came to look. What we found was paradise." With the help of their Dutch co-owners Trienke Lodewijk and Peter De Wit, whose dream was also to build a diving camp, the couple spent five years creating Nuarro.

The 12-room lodge on the shores of northern Mozambique is as eco as can be, with solar panels and wind turbines, wells and menus using fresh ingredients from the local market, which are skilfully turned into delicious dishes by trainee village chefs, with the help of their American food consultant Michelle Gilardi.

After my three-day stay, I felt completely at home in the relaxed 24-bed retreat. At night, I sipped mango cocktails and ate fish under the stars. In the day I swung in a hammock, strolled in waves on a white beach, checked out the school and clinic built with guests' donations, and walked into the traditional African village to play with local children. And one afternoon I did the best thing of all: I snorkelled and then dived on the magnificent reef.

Having refreshed my skills at the well-equipped Padi school, I soon realised why the divers had chosen this bit of coast for their home. For the first 20 minutes, swimming out from the beach, the reef slowly descends from four metres to 12, with shoals of dazzling multicoloured creatures darting about in the glimmering jade waters. Then suddenly the earth drops down, in some places 40 metres, in other parts a whopping 2,500 metres: a vertical wall of pink brain shapes, red fans and jellied lumps in waters that turn from turquoise to almost black. It was one of the most magnificent coral walls I had ever seen: unspoilt and utterly thrilling.

You don't go to Mozambique, I slowly appreciated, to indulge in man-made delights like slick hotels, prompt airlines or comfortable roads (none of which seem to exist). You go to see the Earth at its most raw and beautiful.

To walk stretches of powder-fine white beaches without another footprint on them. To gasp at a voluminous orange full moon rising at 9pm over the dark sea, its mountains visible with bare eyes. And to marvel at the energy and enthusiasm of this country, desperately trying to rebuild itself.

While places like Beira probably need razing in parts rather than rebuilding, one island in Mozambique is so special that in 1991 it was classified a Unesco World Heritage Site.

During the 16th century, Ilha de Mozambique became the site of southern Africa's first European city. Settled by the Portuguese as a trading port from which to export gold, ivory and slaves, the town soon had a tiny church (thought to be the Southern Hemisphere's oldest European building, constructed in 1522), formal streets with Portuguese-style shuttered buildings, a hospital and a school.

Extraordinarily, in 500 years, very little on the tiny two-mile island has changed. As you explore the three streets, you feel as if time has been frozen. The walls of the 16th-century castellated stone fort – about the size of Edinburgh Castle – still drop into the sea, to repel invaders. A brick-red church spire soars into the skies. The dignified hospital has grand pillars and elegant high windows, like a National Gallery building.

The buildings are mostly derelict. But slowly, NGOs and investors are piling funds into restoring the island, and there are now six guesthouses (the nicest, Terraço das Quitandas, is beautifully restored and furnished with exotic Indian Ocean treasures), a few cafés and a bar or two. There is talk of the hospital being turned into a six-star hotel, of slick South African chains being involved in restoration, of rich Italians buying old mansions.

But none of these happen fast. As one local put it, "until you move the poor population of 17,000 off and improve the open drains, which will take political will, I don't think we'll witness any tourist impact for a while. Come back in 10 years and it will still be the same derelict place."

Where political will – and vast amounts of American finance – has without doubt had an impact is Gorongosa National Park. At its peak in the Sixties, the 1,500-square-mile park – four hours' drive from Beira – was considered the most beautiful wildlife reserve in the world. Visitors such as Cary Grant came to witness the vast herds of up to 2,500 elephant, 14,000 buffalo and 500 lion.

When the American voicemail pioneer Greg Carr visited the park in 2004, he was so shocked to discover how few animals had survived that he pledged $40 million (£26 million) to help the government resuscitate the park. In 2008, a young Zimbabwean, Jocelyn Janisch, and her husband, Rob, opened its first private tented safari camp, Explore Gorongosa.

As I explored the park from their simple but comfortable camp, with its six khaki canvas tents and secluded bush bathrooms, I found it easy to see why they, too, came to Mozambique and stayed.

Plants range from desert palms and giant fig trees to mountain cycads, with plains of verdant grasses. Herds of rare sable, waterbuck, nyala and kudu sheltered in shaded forests. By the light of the torch at night, we saw bushbabies, a snake and a lioness darting into the road. And in the morning, walking with an armed ranger, we found a newly hatched batch of crocodile eggs and then spotted yellow-eyed babies sunbathing on waterlily leaves.

It certainly wasn't what you would call a big-game experience – and the camp won't offer that for a while yet. Residents of the surrounding villages are still being educated about conservation and rewarded for not poaching with hospitals and schools. Stocking game is expensive (buying a single rhino can cost $50,000). But for a couple of nights, the camp is definitely a worthwhile stop-off – particularly for those whose budgets might extend to private planes, which can whizz guests in from the glamorous islands in the Bazaruto Archipelago or up into the beach resort of Nuarro (soon to have its own airstrip) in just over an hour.

On this trip – my third in three years – I spent too much time in cars (the country is vast, in summer temperatures rise to over 100F/40C, storms frequently take over afternoons, and roads are poor). If I could do it again, I would spend £500 more and do all transfers by light aircraft.

The views from the air of rust-coloured muddy African rivers spewing into the bright-blue Indian Ocean, of dozens of exotic sand-fringed islands dotting the seas, of little dhows flitting across aquamarine lagoons, are a delight. And if you are really lucky, as I was last year, and see a whale from the air, the extra expense will be worth every penny. In October, I am told, entire pods come in with new calves at Nuarro to take shelter. I know what time of year I am going there next.