Over 120 of the world's active volcanoes can be found dotted around Indonesia, often with settlements clinging precariously close to the smoldering rims.
With frequent volcanic eruptions and earthquakes, Indonesia has the daunting honor of being the world's most geologically tumultuous country. Indonesia's position between the Eurasian and Indo-Australian tectonic plates has resulted in scores of volcanoes—both active and dormant—that dominate the horizon.
Visitors to Indonesia have many opportunities to climb active volcanoes. While often challenging, the views from the summit and the thrill of knowing what is going on beneath the surface will have you falling in love with every menacing, foul-smelling caldera.
Perhaps easiest of Indonesia's volcanoes to enjoy, the multicolored Kelimutu lakes are a popular stop in Flores. Kelimutu's three crater lakes continuously bubble and boil; the other-worldly colors change periodically as the chemical composition of the noxious water changes.
Local lore holds that spirits of the dead ascend Kelimutu and come to rest in one of the three lakes, depending on their deeds performed on earth.
Kelimutu is located just nine miles from the small, pleasant village of Moni roughly between the towns of Ende and Maumere in Flores. Most visitors grab shared transportation to the volcano around 4 a.m., enjoy sunrise on the summit, then walk or hitch a ride back to Moni.
Popular with backpackers for its accessibility from Ubud, Gunung Batur rises 5,633 feet above the green Kintamani region of North Bali. Make no mistake, Mount Batur is very active despite the tourist crowds.
Gunung Batur can be climbed without one of the ubiquitous guides loitering around Kintamani. Most trekkers choose to begin their hikes in the village of Toya Bungkah. An average hike takes around two grueling hours to reach the summit. Alternatively, those looking for more of a challenge can tackle Gunung Batur from Pura Jati by scrambling across jagged lava fields. Unpredictable weather adds to the danger.
Rising prominently above East Bali, Gunung Agung is the tallest peak on the island. Gunung Agung is home to Pura Besakih—the most sacred Hindu temple on Bali—which was miraculously spared during a devastating eruption in 1963 when over 1,500 people lost their lives.
Unlike the touristy Mount Batur, climbing Gunung Agung is not for the faint of heart. Although pushy guides in the base village of Besakih insist otherwise, the mountain can be tackled without a tour. Two different routes, both steep and hazardous, crisscross up the volcano to the summit.
The route from Pura Besakih goes to the highest point on the rim while the route beginning from Pura Pasar Agung on the southern slope is more strenuous.
Towering 12,224 feet above Lombok, Gunung Rinjani is a challenge for even experienced trekkers. Most tourists stop at Rinjani's crater rim for the best views of glowing lava oozing from the cone centered in the crater lake.
Trekking Gunung Rinjani requires stamina, camping equipment, and a guide. Continuing the last 3,000 feet to the summit is possible only if weather and the temperament of the volcano permit; your guide makes the final call.
Treks are not cheap, but they include a guide, food, and equipment, and the rewards are unforgettable. The village of Senaru on the north side of the volcano serves as base where equipment and tours can be arranged.
Although not the highest peak, Gunung Bromo is certainly the most famous in East Java. The summit, situated at 7,641 feet, both attracts and freezes thousands of tourists a year. Gunung Bromo's status was raised to “alert” in November 2010, although the last eruption took place in 2004. Despite the cold temperatures and threat of new activity, tourists still flock up the slopes before dawn to witness a spectacular sunrise from the summit.
Tourists have several options for enjoying Gunung Bromo, including jeep tours or making their own way from the village of Cemoro Lawang. Mount Senaru and Mount Batok, Bromo's neighboring peaks, can also be climbed for amazing views of the eerie “Sea of Sand.”
While not the grandest of Indonesia's volcanoes, Gunung Sibayak in Sumatra has been luring people to the summit for centuries for the amazing views. At 6,870 feet, climbing Gunung Sibayak takes between two to three hours, depending on the route chosen. Optional guides can be hired for a small fee.
Most people begin up Gunung Sibayak just northwest of the town of Berastagi. Alternatively, some backpackers choose to hire a guide and trek from Air Terjun Panorama—three miles north of Berastagi; the challenging trek takes around five hours.
Although Gunung Sibayak has not erupted in over a century, steam vents on the slopes indicate that the volcano is very much still alive.
To get to Anak Krakatau in the Sunda Strait, you need to ride a speedboat from Carita or Anyer on the west coast of Java Island. After more than an hour speeding west into the middle of the strait, you’ll see it looming in the distance: a smoking peak rising about a thousand feet from the sea.
Anak Krakatau is possibly the youngest island in Southeast Asia. The present island broke through the water in August 1930, a cone of volcanic ash that grew in the place of an island that blew apart in 1883. That island – known to the world as Krakatoa – exploded in a cataclysm four times as strong as a modern-day hydrogen bomb. The explosion created a 130-foot-high tsunami that killed over 20,000 people, spawning tidal forces that swept bodies and debris as far away as Zanzibar in Africa.
Life has found a foothold in a slim margin on Anak Krakatau’s eastern side; you can land on the beach and trek up a trail, walking past a stunted forest onto a gigantic ash slope until you reach the outer caldera rim area called "Level One".
Read more about climbing Anak Krakatau, Sunda Strait, Indonesia. For images of a trek up the volcano, read this Tour of the Anak Krakatau (Krakatoa) Volcano, Indonesia.