The boat dropped anchor by a tiny green island with an even smaller sandy beach. We sat in the sun, 20 of us on the upper deck, as a cloth was spread at our feet. From a wood-burning stove on the lower deck came a dish of seafood. Then a second, a third, a fourth ... soon you couldn't move for plates.

The boat was an old fishing vessel, painted blue and red; the sort the Vietnamese boat people once escaped in, now used for taking people on day trips to the islands off the seaside town of Nha Trang. We snorkelled over coral at one island; had lunch and a lazy swim at the next, fruit and tea at a third, and finally stopped at a fishing village, where the children came out to fetch us to shore in round coracles.

Not surprisingly, with 2,000 miles of coastline, the sea has always been important to the Vietnamese economy. Now, with the growth of tourism, it has become even more so as word spreads of long, deserted beaches. But the developers are moving in already. Vung Tau, just two hours from Ho Chi Minh City, is already being touted as Vietnam's answer to Pattaya in Thailand. Nha Trang, six or seven hours around the coast, is their next target, but for now it still has the atmosphere of a small town with a few good hotels, rather than an international resort.

The increasingly prosperous residents of Hanoi and Saigon ride mopeds, but everywhere else I went in Vietnam the bicycle predominated. In Nha Trang I hired a bike, launched myself into the traffic and headed out of town. Fringed with palm trees, the road along the beach was dotted with cafes that had faded old deckchairs on the porches. I stopped at a little open-fronted wooden hut with low wooden stools. The owner's 15-year-old daughter sat with me while I drank my iced coffee. She wanted to practise her English. No, they didn't have to learn Russian any more at school, they could learn English. Some people learnt French, but English was more useful. She wanted to go to university. And she wanted to travel. Had I heard of Cindy Crawford? Kate Moss?

The beach at Nha Trang seemed to stretch for ever. It was everything a seeker of perfect sand could want; and if you lay there long enough (about five minutes) someone would come along to sell you a coconut, fruit or a steamed pork bun or offer you a massage.

If you prefer uncommercialised sunbathing there are plenty of other good beaches. We had driven past tiny coves on the way from Ho Chi Minh City, and stopped at one where 40 or so children joined us, splashing around fully clothed in the water. China Beach and Lan Co, both with white sand and requisite palms, are near Danang where US troops first landed in 1965 and where a new invasion, this time of cruise ships, is under way.

Just south of Danang is the overgrown village of Hoi An, which was a prosperous trading port in the 17th and 18th centuries until the river silted up. Now most of the old, carved wooden houses have been turned into shops, restaurants and museums. From here it's possible to hire a motorbike with driver to take you to some of the local sights. Which is how I found myself sitting on the back of a bike driven by a stranger who didn't speak English, being jolted along on what just might be the worst road in the world on the way to the ruined Cham temples of My Son, about 60 kilometres (40 miles) inland. After the first 10 kilometres I'd been so thoroughly shaken I thought of begging the driver to turn round and take me to the beach instead.

Two hours later, after a ferry crossing and a change of driver and bike for the final stretch (the villagers guard their access to the site closely) I was dropped off at the entrance. I pushed my way down a narrow path, and then brick structures loomed out of the jungle, covered with plants. It was very hot, the air smelt humid, and there were bright blue butterflies and inky-black ones. I wandered around for hours, trying to imagine what it had been like when this was the religious centre of the Hindu Champa kingdom that had once dominated central Vietnam. But the heat finally defeated me and I got back on the bike and hardly felt the potholes as we went back to Hoi An.

On the way we passed people harvesting rice and threshing it with a pedal-powered mill, spreading the grain in flat round baskets by the roadside to dry. The air smelt of newly cut grass, and the breeze was cool. A local bus that looked like a survivor of a demolition derby drove past, and I was glad I wasn't on it. Ahead of me lay the beach and an iced coffee, then fish for supper at the Cafe des Amis with some fellow backpackers. And no one had mentioned the war.

How to get a visa

Application forms and tourist visas are available in person or by post from the Vietnamese Embassy at 12-14 Victoria Road, London W8 (0171-937 1912). A one-month visa costs pounds 40.

Getting there

Cheap flights to Hanoi or Ho Chi Minh City on Aeroflot (via Moscow) are around pounds 700 through agents such as Regent Holidays (0117-921 1711). Discounted tickets on many other airlines are available, particularly on Thai and Cathay Pacific.

Where to stay

In Nha Trang, Vien Dong Hotel, 1 Tran Hung Dao St; rooms from $25 a night. In Hoi An, Hoi An Hotel, 6 Tran Hung Dao St; $6 per night for dormitory accommodation.

How to stay healthy

No vaccinations are compulsory, but precautions are recommended against tetanus, polio, cholera, typhoid, hepatitis and malaria. A mosquito net will enhance your chance of getting some sleep.