Nha Trang or Phnom Penh?

Nha Trang is built around the sea. A sandy crescent runs the length of the centre behind a palm-lined promenade, and boats take you out to island bays with clearer water. Doc Let and the empty sand south towards Cam Ranh add more choice, though in the autumn monsoon the town beach can be choppy or closed to swimmers.

Phnom Penh has nothing like this. It is an inland city on the Mekong and the Tonle Sap, the rivers are not for swimming, and the nearest coast at Kep is about three hours away. The only place to cool off is a pool.

You eat equally well in both, but the cooking is different. Nha Trang's table is the sea, with crab, squid and clams grilled at outdoor tables. Local dishes include bun cha ca fish-cake noodles and nem nuong pork rolls, though the tourist streets drift towards pizza.

Phnom Penh serves Khmer cooking, which is herbal and built on fish paste, lemongrass and Kampot pepper, from fish amok to a breakfast of bai sach chrouk in the market food halls. Its French legacy of baguettes and cafés, and a few kitchens that rework Khmer dishes for fine dining, give it more range at the top end.

Phnom Penh has far more to see. The Royal Palace, the Silver Pagoda and the National Museum stand together near the river, and Tuol Sleng and Choeung Ek give a sobering account of the Khmer Rouge years. That is enough for two or three days.

Nha Trang's sightseeing fits into one day: the Cham towers of Po Nagar, the white Buddha at Long Son Pagoda, the cathedral and the Yersin museum. Most of the town is modern hotels, and people come for the water.

Phnom Penh has the better night out for adults. There are rooftop terraces over the Tonle Sap, small cocktail and craft bars around Bassac Lane, and late clubs near Street 51. The scene is compact and rough in places, and bag snatching from passing motorbikes is a known risk.

Nha Trang's evenings are beach-resort fun: backpacker bar crawls, fire shows and DJ nights on the sand, or beer over grilled seafood with local groups. It is good for a few nights, but not a reason to choose the town.

Nha Trang has the scenery: a bay ringed by steep green islands, with mountains behind the town. The protected waters around Hon Mun are among Vietnam's favourite places to dive and snorkel, and the Ba Ho falls and the Hon Ba hills make good half-day trips.

Phnom Penh sits on flat floodplain, so being outdoors means sunset boat trips, cycling on Koh Dach island or a visit to the Phnom Tamao rescue centre. The nearest real forest is at Kirirom, a long drive away.

Neither city is a strong base for day trips, but Phnom Penh has a little more within reach. You can visit the stupa-covered ridge at Oudong, the lakeside temple at Tonle Bati, Phnom Chisor and the pottery town of Kampong Chhnang, which makes several quiet days out.

From Nha Trang the main outing is to the Cham towers at Phan Rang, about two hours south, plus boat trips to island villages such as Binh Ba. From both cities the famous places, Dalat or Angkor, need an overnight stay.

Nha Trang works far better with children. It has a long sandy beach, rides, a water park and an aquarium on Hon Tre, turtles at the Oceanographic Institute and mud baths to wallow in. The scooter traffic and the rough autumn sea are the drawbacks.

Phnom Penh welcomes children warmly, but its key sights are no place for them, there are few pavements and the heat never lets up. The hotel pool and the play areas in the malls end up filling much of the time.

In both cities there is no rail, most journeys are by ride-hailing, and crossing the roads takes nerve. Nha Trang has a walkable seafront promenade that links the hotels, restaurants and beach, though the airport is about 35km out and the islands need a boat.

In Phnom Penh the tuk-tuk is the usual ride. The riverfront sights are close together, but broken pavements make walking between them slow.

Phnom Penh is the better place to shop. The Russian Market sells silk, silver, carvings and overrun clothing from local garment factories, Central Market trades under its art deco dome, and the boutiques and fair-trade shops around Street 240 offer good Cambodian textiles and crafts.

Nha Trang has the round Cho Dam market hall and a night market for souvenirs. Its regional specialities are pearls and agarwood, but beyond those there is little more than beachwear and a couple of malls.

Both are very cheap by Western standards, and in much the same way: street food, coffee, short rides and massages cost little. The difference is where the money goes. In Nha Trang the costs that climb are linked to the sea, with dive and boat trips, the island amusement park and seafood priced by weight. In Phnom Penh it is imported wine, Western restaurants and international hotels.

Phnom Penh has one thing well worth an evening: classical Khmer dance. It was rebuilt by the Royal University of Fine Arts after the Khmer Rouge years and is staged with shadow puppetry near the National Museum, with larger occasions at the Chaktomuk Theatre. A few bars add jazz and local bands.

Nha Trang offers little beyond cover bands in beach bars and the occasional show of Cham music and folk dance for tourists.

Nha Trang is the easier place to unwind. The mud-bath parks near the Thap Ba hot springs make a relaxing half day, there are massage shops on most streets, and the resort spas in the bays outside town are quiet, even though the high-rise centre is noisy.

Phnom Penh relies on massage, from street parlours to blind-masseur centres and NGO spas, and its boutique hotels have garden pools. It has no bathing tradition, and the traffic and dust are back as soon as you leave the hotel.