Bali or Zanzibar?

The sea is equally warm around both islands, so the difference is in the sand and the swimming. Bali's best-known stretch, from Kuta to Canggu, is a surf coast with strong rips, and swimmers there stay between the flags. For calm water you go to Sanur or Nusa Dua behind the reef, and the prettiest coves lie under the Bukit cliffs, some at the bottom of long stairways.

Zanzibar has the classic white-sand beach with palms behind it. At Kendwa and Nungwi in the north the water is deep enough to swim at any tide. The east coast is less easy, because at Paje and Jambiani the sea pulls back hundreds of metres at low tide, so swimming there depends on the tide table.

Bali gives a food lover much more to explore. Its Hindu kitchen, with babi guling, bebek betutu and lawar from simple warungs and the Denpasar morning markets, is unlike the rest of Indonesia. Canggu, Seminyak and Ubud add coffee roasters, brunch spots and tasting menus.

Zanzibar's spice-trade cooking is at its best in Stone Town, where the Forodhani evening stalls, urojo soup and clove-scented pilau make a memorable first night. On the beaches the choice narrows to grilled fish and resort buffets.

Bali's culture is spread across the island and is part of daily life. There are sea temples at Tanah Lot and Uluwatu, Besakih on the slopes of Mount Agung and the subak rice terraces of Jatiluwih. Ubud adds its palace and painting museums. Seeing it all takes long drives, but a procession you happen upon can be the highlight of the trip.

On Zanzibar nearly everything is in Stone Town. Its carved doors, the Palace Museum of the Omani sultans and the cathedral on the site of the old slave market make a moving day or two on foot. Beyond the town there are a few ruined palaces and the Persian baths, but there is less to fill a longer stay.

Bali's southwest offers a real night out in several styles. Beach clubs at Seminyak, Canggu and Uluwatu run from the afternoon pool into the night, Seminyak has polished cocktail lounges, and Kuta and Legian have cheap clubs open until the early hours.

Zanzibar's evenings mean bonfires and beach bars at Nungwi and Kendwa, kitesurfer bars in Paje and rooftop sundowners over Stone Town's harbour. The full-moon party is the one big night. Otherwise there are hardly any clubs, most places are quiet by midnight, and Ramadan quietens things further.

This is where the two islands differ most. Bali is volcanic. You can make a pre-dawn climb to Mount Batur's crater rim, see misty crater lakes and waterfalls around Munduk, and walk or cycle the rice valleys at Sidemen. Divers have the Tulamben wreck and the manta rays off Nusa Penida, and surfers come from around the world for the reef breaks of the Bukit.

Zanzibar is a flat coral island, so its outdoors is gentler and on a smaller scale. Red colobus monkeys live in Jozani Forest, and the protected reef at Mnemba atoll gives clear snorkelling with turtles. Boats from Kizimkazi go out looking for dolphins. The island's real strength is kitesurfing on the shallow lagoon at Paje and Jambiani, where steady trade winds blow through two long windows each year.

Neither island is a strong base for outings, but Bali offers a little more. The Bali Aga villages of Tenganan and Penglipuran keep older customs, Sidemen and Amed make a slow day in the east, and Nusa Lembongan is a short fast-boat ride from Sanur. Traffic means most people manage only one or two.

Zanzibar's outings are smaller in scale. You can see the giant tortoises on Changuu, swim from a sandbank, take a spice-farm tour with lunch or visit Kizimkazi's old mosque. From the beaches, Stone Town is the main day out, and Dar es Salaam or Pemba need an overnight stay.

Bali is easier with children, as long as you base yourselves in Sanur or Nusa Dua. Both have calm reef-sheltered water, kids' clubs and flat beachfront paths, and there are a water park, a safari park and private-pool villas. The hard parts are roads without pavements, rabies and long drives.

Zanzibar works for a plain beach stay at a north-coast resort. Children enjoy the Changuu tortoises and the Jozani monkeys, but little else is made for them. Malaria precautions and limited medical care make it the harder choice with young children.

Both islands depend on taxis and drivers, but Zanzibar is easier. Stone Town is best explored on foot, the main roads are paved, the north and east coasts are about an hour away, and beach villages can be walked along the sand.

Bali has no public transport a visitor can really use. Traffic clogs the south between the airport, Seminyak, Canggu and Uluwatu, and pavements are often missing. Most people hire a driver by the day, and scooters are only for experienced riders.

Bali is the better place to shop. Along the road to Ubud, Celuk is known for silver, Mas for woodcarving and Batubulan for stone carving. Seminyak and Canggu have boutiques run by island-based designers, selling linen, ceramics and furniture.

Zanzibar's shopping comes down to Stone Town's lanes and Darajani market. You can buy cloves and vanilla by the bag, kanga cloth, Tingatinga paintings and tanzanite, with haggling expected. The beach villages offer little beyond souvenir stands.

Your money goes further on Bali. Villas with private pools, warung meals, massages and drivers by the day all cost little, especially inland and on the east and north coasts. Only the beach clubs and cliff-top resorts charge close to Western prices.

Zanzibar has cheap guesthouses in Stone Town and simple bungalows around Paje. Much of the island's accommodation is mid-range to upmarket, though, and taxis, diving and boat trips are priced for visitors and add up quickly.

Bali's dance tradition is easy to see. Ubud holds Legong, Barong and shadow-puppet performances with gamelan almost every night, and the Kecak is chanted at sunset on the Uluwatu cliffs. In the dry season the Bali Arts Festival in Denpasar brings village troupes together.

Zanzibar's own music is taarab, which you can hear at Stone Town's music school and in its cultural halls. The town also holds dry-season festivals of East African music and film. Elsewhere on the island, live music mostly means hotel drumming evenings and beach bands.

Rest and renewal are among the main reasons people go to Bali. Ubud and its valleys are full of yoga studios, retreats and spas set among rice fields. There are hot springs at Banjar and Lake Batur and a purification ritual at Tirta Empul, while Sidemen and Amed offer real quiet.

Zanzibar's calm comes from its pace rather than its facilities. Days in the beach villages follow the tide, and resort spas offer massages with coconut oil and spices. Yoga is easy to find around Paje and Jambiani, but there is nothing like Ubud's range of retreats.