Lured by black sand beaches, exotic landscapes and deep spirituality, Bali has been a dream destination for decades.

Diverse accommodation options, a wide variety of activities and a thriving restaurant and nightlife scene make it a prime choice for Singapore travellers looking for a quick getaway. This is buoyed by the more than 15 flights to Bali from Singapore every day.

Its unwavering popularity means that on a long weekend like this one, many flights are sold out months in advance.

But decades of development and a continuous stream of foreign tourists have saturated the market, and favourite Bali locales such as Nusa Dua, Seminyak and Ubud have started to lose the charm which made them so appealing in the first place.

When Ubud, the cultural and artistic heart of the island, has a Starbucks on its main road, and the restaurants, bars and shops between Kuta and Seminyak throng with foreign faces - your colleague's or neighbour's, possibly - going to Bali these days does not always feel like you are getting away.

Bali is such a holiday institution in the minds of travellers that it is easy to forget that it is just one of more than 17,000 islands which make up the Indonesian archipelago.

Singapore now has 14 direct flights and four direct ferries to Indonesian cities, and more are easily accessible through a short stopover in Jakarta or Kuala Lumpur.

The travel time to some destinations may be a little longer than the roughly three-hour flight to Bali, but tickets to cities such as Surabaya or Yogyakarta often cost half or a fraction of the price.

Now, as volcanic ash from Mount Raung in Java threatens to cancel flights in and out of Bali, it is as good a time as any to think beyond Bali and explore the other unique islands that Indonesia has to offer.

Mount Bromo

Indonesia offers world-class hiking and trekking and one of the most mesmerising trails is found in Bromo Tengger Semeru National Park in East Java.

It is named after its two famous mountains - Mount Semeru, the highest in Java at 3,676m which billows smoke into the air roughly every 20 minutes, and picturesque Mount Bromo, recognisable by its missing top half, which was blown off in an eruption - and the Tengger people, one of the few Hindu communities left in Java.

Mount Bromo is one of Indonesia's most active volcanos and constantly releases sulphurous smoke from its crater. It is safe to climb though and thousands of people do so every year.

The most popular way to experience the mountain is to watch the sun rise over its caldera from nearby Mount Penanjakan. The hike to the lookout point takes one to two hours, depending on your fitness level and the number of people on the trail. There are normally not too many, as most tourists hire a car to take them to the lookout point in time for the sunrise at 5.30am.

The lookout point is packed with people and you might have to jostle to get a view of the mountain if you are not early enough. The pink light of dawn on Mount Bromo is beautiful, but hiking up in broad daylight is a good way to beat the crowds.

After sunrise, hike down Mount Penanjakan and into Tengger caldera, across 3km of soft, swirling volcanic sand to the base of Mount Bromo, where you can climb 253 steps to the top.

After the hike, spend some time in Malang, a quieter and calmer city than the busy port city of Surabaya. Its cooler climate and pleasant landscape attracted Dutch colonials and some of their historical buildings still lend their charm to the city.

Visiting tea, coffee and apple plantations is also a popular pastime in the area.

It is best to go in the dry season from April to October and be sure to pack a jacket and gloves as it is cold in the mountains. Temperatures are regularly in the low teens during the day and drop to single digits at night.

GETTING THERE

The flight from Singapore to Surabaya takes two hours and 20 minutes and Singapore Airlines, SilkAir and Jetstar offer daily flights. Tigerair flies there six days a week.

From Surabaya, take a taxi or hired car to Malang, which is three hours away. Stay in Malang or a nearby village for easy access to the national park and the surrounding plantations.

Sumba

Rolling limestone hills, low-lying grasslands and fields of maize distinguish Sumba, a rural island roughly 300km east of Bali, from the rainforest-covered landscapes one expects in Indonesia.

The people are also different. Sumba is populated by tribal people of an ethnically and linguistically diverse mix of Austronesian and Melanesian ancestry. They are predominantly Christian, though they retain much of their tribal heritage, including rare, above- ground burials, animal sacrifices and Pasola, a harvest festival held in February or March in which hundreds of members from different tribes charge at one another while on horseback, hurling wooden spears. These days, it is a ritual battle, but blood still needs to be spilled to ensure a good harvest.

Sumba is one of Indonesia's poorest islands, but the kampung communities there are well known for their detailed, hand-woven ikat fabric, which has found its way into museums and private collections around the world.

Sumba is also renowned for its surf and, in particular, the rare left-hand barrel wave on its western coast. Known as Occy's Left, the wave is one of Asia's most consistent surf breaks and professional and amateur surfers pay top dollar to enjoy the ride.

It is accessible only to guests of the popular, eco-luxury Nihiwatu Resort (www.nihiwatu.com), the only high-end resort on the island. Only 10 surfers are allowed on the wave each day, and it costs US$100 (S$138) to reserve the spot.

GETTING THERE

Singapore Airlines, Tigerair, Jetstar, Qantas and Garuda all have morning flights from Singapore which get to Bali's Denpasar airport in time for the hour-long Garuda flight to Sumba's Tambolaka airport, which leaves daily at 1pm.

The return Garuda flight from Sumba to Denpasar is at 11am daily.

Mentawai Islands

People venture to the Mentawai Islands off Sumatra's western coast for two reasons: to trek and to surf.

The islands offer some of Indonesia's best and most consistent surf breaks all year round, with more than 25 named waves to choose from and "secret" waves you will learn of only when you get there.

The handful of resorts on the islands cater to surfers, often providing kayaking, snorkelling and fishing equipment as well.

Siberut is the largest of the islands and home to the majority of Mentawaians, an animistic huntergatherer people who had little contact with the outside world until the late 19th century. Even then, unpredictable currents, sharp coral and strong winds meant they were mostly left to themselves.

Traditionally, the Mentawaians live in uma - bamboo and thatched roof longhouses raised on stilts - and many of the 64,000 who live on the islands maintain their customs, including the ritualised sharpening of teeth and getting body tattoos.

Some organise treks through dense jungle, taking tourists to visit traditional villages, where they spend the night in uma along the way.

The jungle itself is an attraction. It is thought that the islands broke off from Sumatra 500,000 years ago, which created a unique ecosystem. About 60 per cent of the terrestrial animals on the islands, now a Unesco biosphere reserve, are found only here.

GETTING THERE

The closest airport to the islands is in Padang, the capital of West Sumatra. The quickest way to get there is with a Tigerair flight to Kuala Lumpur, followed by an AirAsia flight to Padang, and the whole journey takes less than five hours.

Garuda also flies to Padang daily via Jakarta, which takes about 51/2 hours.

From Padang, take a ferry or speedboat to your island destination. This is typically organised by the resort.

Pulau Weh

Cast away your worries on Pulau Weh, where idyllic island life is spent swinging on a hammock under the shade of a coconut tree.

White sand beaches and some of the best snorkelling and diving in Indonesia await visitors to this small, sleepy island at the northernmost tip of Sumatra.

Located off the coast of Banda Aceh in the Andaman Sea, tourism opened up here only a decade ago and it is still mostly undeveloped.

Most of the locals here are fishermen who live in the quiet main town of Sabang, also known for its production and sale of rattan furniture. Tourists arrive here by boat and move on to beautiful beaches a 20-minute drive to the west.

The two main beaches with accommodation for tourists are Gapang and Iboih.

Gapang beach has dive shops, rustic hotels with sea-facing bungalows and a handful of restaurants and cafes.

Iboih, a 10-minute drive northwest of Gapang, is a backpacker's haven, with a few basic hostels and inns lined along a pristine, sandy beach.

About 100m off Iboih is a coral reef called Sea Garden, which is great for spectacular snorkelling - turtles, stingrays and lion fish can be found here.

Diving around Pulau Weh is also highly recommended, with steep, jagged cliffs of coral, large sunfish, moray eels, manta rays and even whale sharks from November to January.

The whole island is only 156.3 sq km, a fifth the size of Singapore, but it is mountainous, with a small active volcano in the centre and a bubbling hot spring to the south.

With its mix of diving enthusiasts and backpackers and its laid-back vibe, Pulau Weh is what the Gili Islands off the western coast of Lombok used to be, before the corrosive overflow of Bali's tourism reached its shores.

The island is an offbeat gem and a welcome escape for those looking for simple pleasures.

GETTING THERE

AirAsia has daily flights to Banda Aceh via Kuala Lumpur. They cost about $200 return and take about 41/2 hours.

From Banda Aceh, take a 30-minute taxi ride to Ulee Lheu Port to board a fast (45-minute) or slow (two-hour) ferry to Sabang on Pulau Weh.

Yogyakarta

Yogyakarta is the cultural heart of Java, but its main attractions are the ancient monuments nearby. Use the city as a base from which to explore the astounding Borobudur Buddhist sanctuary and Prambanan Hindu temples, both Unesco World Heritage sites.

A marvel of the ancient world akin to Angkor Wat in Cambodia, Borobudur is the world's largest Buddhist monument and wraps itself on an 118m by 118m area up and around a small hill.

It was buried under layers of volcanic ash until Sir Stamford Raffles, then governor of Java, gave the order for it to be cleared in 1815.

Built between the 8th and 9th centuries in the peaceful rural heartland of central Java, it is composed of six square terraces topped by three circular ones, with finely carved gateways, stupas and scenes from Javanese life etched into stone. The structure is thought to be a walk-through mandala, a spiritual symbol representing the universe, and devotees can walk around the bottom terraces of the structure, which represent the everyday world, before gradually making their way to the top circular terrace representing nirvana, or enlightenment.

This mystical site is best experienced at sunrise or sunset. On Vesak Day, Buddhism's holiest day, which celebrates the birth and death of Buddha, a procession of saffron-robed monks pray, chant and light candles all around the temple.

Borobudur is an hour's drive outside the city and is easily accessible by taxi, bus or hired car.

Prambanan temple is closer, just 17km north-east of Yogyakarta.

This beautiful temple complex, the largest Hindu monument in Indonesia, was built between the 8th and 10th centuries and lay in ruins for hundreds of years before restoration started in the 1930s. The compound contains the remains of more than 200 temples, with eight main temples standing up to 47m tall in the central courtyard. The intricately carved stone temples boast vibrant scenes of the Ramayana, with motifs of lions, birds and heavenly trees.

West of the temple complex is an outdoor theatre, where visitors can watch the famous Ramayana epic unfold with the complex lit in the background. More than 200 performers dance and sing the story over four successive nights two or three times a month during the dry season from May to October. Or watch the full story, condensed into a two-hour performance, nearby at the Trimurti Covered Theatre from November to April.

GETTING THERE

AirAsia flies daily to Yogyakarta from Singapore and SilkAir flies there four days a week. The non-stop flight lasts two hours and 20 minutes.

Sulawesi

Indonesia's most bizarre-looking island may also be its most interesting. Sulawesi's unique, many-armed shape is indicative of the many different landscapes, cultures and ecosystems which have evolved here. From colonial architecture to astonishing tribal culture to world-class diving, Sulawesi has something for everyone.

Most trips start in Makassar, a busy port city and the capital of South Sulawesi. Here, you will find buzzing nightlife and some of Indonesia's best examples of Dutch colonial architecture at Fort Rotterdam, built in 1667.

Those looking for extraordinary diving should head to south-east Sulawesi and Wakatobi National Park between the Banda and Flores seas. You can fly to Wangi-wangi, one of the park's largest islands, from Makassar; or, as a guest of Wakatobi Dive Resort, catch its charter flight to and from Bali.

Any trip to Sulawesi would not be complete without a stop in Tana Toraja, a cultural island tucked into the rugged mountainside of south Sulawesi. It is home to the Toraja, an indigenous ethnic group which has maintained many of its traditional ceremonies despite being converted to Christianity by the Dutch a century ago. The Toraja are famous for their tongkonan traditional houses with distinct, peaked roofs, as well as elaborate ceremonies, none more so than the tomate funeral ceremony.

Hundreds of Toraja attend the funerals, which go on for days and include ritual buffalo sacrifices to celebrate the life of the deceased before they are buried in graves dug deep in caves on the mountainside.

To witness these elaborate ceremonies, visit during the funeral season in July and August, when the Toraja bury their dead.

Trekking is one of the best ways to visit some of the more remote villages, and excellent white-water rafting can be found here too. Use Rantepao town as your base to explore the picturesque area.

GETTING THERE

SilkAir flies to Makassar on Wednesdays and Saturdays and returns on the same days. The non-stop flight takes three hours.