Ha Long or Hoi An?

Ha Long's town beach at Bai Chay is made of imported sand, and its water is shallow and often cloudy. The better swimming is off the deck of a cruise boat or at island stops such as Ti Top, while the best sand needs an overnight trip out to Quan Lan. In winter the sea is too cool for most people.

Hoi An has the real coastline. An Bang and the long, open shore running north towards Da Nang are a bicycle ride away through the paddies, and from spring to late summer the sea is calm enough for easy swimming. The trade-off is the autumn monsoon, when surf and red flags make it a beach to walk on rather than swim from.

Both towns are cheap places to eat well at street level, but Ha Long's strength is narrow. It comes down to springy squid cakes and seafood picked from the tanks at Hon Gai's market halls and on the Bai Chay waterfront. Cruise set menus and large, impersonal tourist restaurants fill the gaps.

Hoi An has a cooking style of its own: cao lau, white rose dumplings, chicken rice and its well-stuffed banh mi. Cooking classes that start at the market or in the Tra Que gardens are a local speciality. Neither town is strong on fine dining, but a food lover has far more to look for in Hoi An.

For history and architecture, the gap between these two is wide. Ha Long is a young city that people visit for the scenery of its bay, and its cultural stops are few and far apart. There is the Quang Ninh Museum in its black glass building in Hon Gai, which is good on coal mining and the province's past, then Long Tien pagoda and the short climb up Bai Tho mountain. A boat visit to a floating fishing village such as Cua Van gives a glimpse of life on the bay, but a curious visitor will have seen everything in a day.

Hoi An is the opposite: one compact, dense whole rather than scattered stops. Within a few streets of the Thu Bon river stand hundreds of old timber shophouses, the Fujian and Cantonese assembly halls, family chapels and the covered Japanese Bridge, many still lived in, so an unhurried walk is the sightseeing in itself. Its museums are modest, yet two slow days here go deeper into history than anything Ha Long can offer.

Neither town suits a big night out. In Ha Long an evening means beer halls, karaoke and seafood in Bai Chay, or a drink on a cruise sundeck and some squid fishing before an early night.

Hoi An is a little livelier. You can walk the lantern-lit riverbank, and there are a few later backpacker bars on An Hoi islet and relaxed beach bars at An Bang. Anyone who wants clubs goes to Da Nang.

Ha Long Bay is the reason to choose Ha Long. Close to two thousand forested limestone towers rise from the water, with caves such as Sung Sot and kayak routes into enclosed lagoons. The quieter Lan Ha and Bai Tu Long bays and Cat Ba's trails and climbing offer more for those who want it.

Hoi An's nature is gentler and lower-lying: rice paddies and vegetable gardens seen by bicycle, basket boats in the Cam Thanh palm waterways and coral around the Cham Islands. The more dramatic scenery is further off, at the Hai Van Pass and on the Son Tra peninsula, and the autumn storms cut much of it short.

Ha Long has one strong outing in Yen Tu, the holy mountain where the Truc Lam Zen school was founded, with pagodas climbing through old forest. The colonial port of Hai Phong and the Bach Dang battlefield are also close by.

Hoi An's options go a little further. My Son's jungle valley of Cham temples is an hour inland, and Da Nang has the finest collection of Cham sculpture as well as the cave shrines of the Marble Mountains. The two big historic cities, Hanoi and Hue, are too far from either town for a comfortable day trip.

Both work well with children, in different ways. In Ha Long the adventure is the bay itself, with caves, kayaks and swimming off the deck, and Sun World's cable car, Ferris wheel and water park on shore. Overnight cruises suit older children better than toddlers.

Hoi An is calmer and more hands-on, with lantern-making, basket boats, cycling through rice fields and sand that suits young swimmers in the calm season. Heat and motorbike traffic are drawbacks in both.

Ha Long stretches along the bay in two halves joined by the long Bai Chay bridge. Beyond the waterfront, most visitors rely on taxis or ride-hailing, and cruises leave from outlying harbours.

Hoi An is easier. Its compact old town is closed to motor traffic for much of the day, and a hotel bicycle covers the flat ride to the beach and the villages. Both towns need a car or driver for anything further.

Ha Long's shopping is limited to the Bai Chay night market, pearl showrooms and the dried seafood and fish sauce of Ha Long market.

Hoi An has a real draw in its tailors, who make suits, dresses and shoes to measure over several fittings. Silk lanterns, ceramics and the An Hoi night market add to that, although much of the stock repeats from shop to shop.

Both are very cheap once you arrive, with low-cost rooms, street food and transport. The difference is where the money goes. In Ha Long the big expense is the overnight cruise. In Hoi An it is the old town's heritage entry fee and the beachfront resorts, and the resorts are easy to skip by staying in a homestay and borrowing a bicycle.

Live performance is thin in both. Ha Long offers staged shows in the Bai Chay entertainment complex and folk singing on some cruise boats, but no venue with a programme of its own.

Hoi An at least has local traditions to join. Visitors can take part in bai choi, the sung card game played in the old town, watch folk music and dance at a traditional arts house, or see a large outdoor show on a river island.

Ha Long's calm is mostly found on the water: dawn tai chi on deck, small spas on the better boats and a quiet night in a sheltered cove. The mineral hot springs at Quang Hanh are about forty minutes east. On land, traffic and tour groups make the town loud.

Hoi An is easier to unwind in from day to day. Life moves at the pace of the river, there is massage at every level and yoga classes are easy to find, and the resorts among the paddies are built for doing very little. It has no hot springs, though, so a traveller who wants to bathe in mineral water will find that only near Ha Long.