Phuket or Krabi?

The beaches are broadly level, but they are set out differently. Krabi's finest sand, at Railay West and Phra Nang, sits under sheer cliffs and can only be reached by longtail boat. The beach in Ao Nang itself is convenient but plain.

Phuket strings its bays along one coast road, so you can pick a beach by mood: crowded Patong, calmer Kata and Karon, quiet Nai Harn or empty Mai Khao. In the monsoon, Phuket's west coast is the more dangerous of the two because of its rip currents, while in Krabi the main problem is that boats stop running.

Krabi's cooking is southern Thai, shaped by its Muslim communities, with khao mok gai and roti at breakfast. It is at its best at the evening market in Krabi Town. It is honest, simple food, but there is less depth, and there is little fine dining.

Phuket eats better, and the reason is Phuket Town. Its Hokkien and Peranakan cooking, with yellow noodles, peppery braised pork belly and morning dim sum with strong coffee, sets it apart from the rest of Thailand. The island adds seafood sold by weight on the waterfront and a layer of upmarket resort dining.

Neither place is a culture destination, but Phuket gives you more to see. Phuket Town's Sino-Portuguese shophouses and tin-baron mansions, Wat Chalong, the Big Buddha and the small museum at Thalang add up to a day or two of sightseeing. Krabi has the Tiger Cave Temple, with its long climb and its views over the karst, and a pleasant riverside walk in town, and not much else.

This is where the two differ most. Phuket has a real party scene. Bangla Road in Patong fills with neon, beer bars and big clubs that run until dawn, and Bang Tao and Kamala add stylish beach clubs at sunset.

Krabi keeps evenings low-key: a short run of bars in Ao Nang, and hammocks, reggae and fire-spinning on Railay. There are no proper clubs, and the people who want a big night usually take the ferry to Phi Phi.

Both are strong, and they differ in how you meet the landscape. In Krabi you are inside it. The cliffs at Railay and Tonsai are among the world's best-known climbing spots, and you can kayak through the mangroves or walk to the Emerald Pool and the Dragon Crest viewpoint.

Phuket looks across the strait at Phang Nga Bay and reaches it by boat. It is the better base for diving, with trips to the Similans in the dry season, and for surfing during the monsoon.

The day trips are much alike, and most of them go by boat to Phi Phi or the Koh Yao islands. Neither place has historic sites within easy reach. Krabi is a little closer to Phi Phi and can add Koh Lanta's stilted Old Town. From Phuket you can reach Khao Lak and the small town of Phang Nga, and each place is a long day out from the other.

Phuket gives children more to do. It has water parks, the aquarium at Cape Panwa, ethical elephant sanctuaries and plenty of resorts with kids' clubs. The catch is that every outing means a taxi on busy, hilly roads.

Krabi's family days revolve around the shallow coves at Klong Muang and Phra Nang, gentle boat trips and the Emerald Pool. It has no attractions built for children, and the open longtail boats need some care with toddlers.

Krabi is the easier of the two, though neither is simple. Its songthaew pickups link Ao Nang, the beaches to the north and Krabi Town on one short circuit. The only awkward part is Railay, which you can reach only by boat.

Phuket is a large, hilly island. Its airport bus runs infrequently and stops early, and the songthaews from Phuket Town do not link one beach to another. That leaves taxis with high fixed fares, or scooters on steep, twisting roads.

Phuket is clearly ahead here. It has large malls with international brands, a big weekend night market, and galleries and batik shops in Phuket Town's old quarter, where Thalang Road becomes a walking-street market on Sundays. In Krabi, shopping means stalls of beachwear and souvenirs along Ao Nang's main road and the weekend market in Krabi Town. There are no boutiques or design shops worth seeking out.

Krabi is the cheaper base. Krabi Town works at local prices, Ao Nang still has plenty of affordable rooms, and only Railay is expensive, since everything there arrives by boat. The costs that build up are island tours and national park fees.

Phuket costs noticeably more. Taxis are the biggest drain, and room rates at the main beaches climb sharply in the peak months. The monsoon brings large discounts if you can live with the rain.

Neither place is for anyone who cares about live arts, though Phuket has a little more on stage. It has large ladyboy cabaret revues and staged Thai cultural shows. Krabi's evenings bring fire-spinning on the beach, cover bands and Muay Thai fights put on for visitors.

Phuket is the stronger choice for a stay built around wellness. It has dedicated retreats with detox programmes, yoga and meditation, and a cluster of Muay Thai and fitness camps in Chalong where people train for weeks. Mai Khao and Nai Harn keep a slower pace.

Krabi has plenty of massage and resort spas, and it has something Phuket lacks: the hot springs at Khlong Thom, about an hour's drive south, where warm mineral water runs into forest pools.