Mount Merapi

Literally "Fiery Mountain", Mount Merapi is the most active volcano in all Indonesia — no mean feat — and it has erupted at least 68 times since 1548. The volcano is thought to be largely responsible for the downfall of the Central Javanese Hindu Mataram kingdom in 1006 and the desertion of the huge temple complex at nearby Prambanan.
Recent eruptions include 1994 (64 killed), 2006 (there were no immediate deaths, but a prelude to an earthquake that killed over 5,000) and 2010 (30 dead).
Anyone thinking of climbing the mountain must first check if it is safe to do so. While climbing the mountain with a qualified guide is recommended it is not necessary or mandatory (locals will tell you otherwise in the interest of a quick buck) as the tracks to the summit are wide and clearly marked.

There are more than three different routes to access Mount Merapi, though recent eruptions and the tendencies of the lahars, ash clouds, and other hazards have favoured the northern access point from Selo, which lies between Mount Merapi and Mount Merbabu.

Selo

Selo is the last village on the way to Merapi. A taxi from Yogyakarta airport to Selo and back will cost you around Rp 1,000,000. Most of the drivers will happily wait for you while you climb Merapi and will take you back to your hotel.
Selo has local guides who will take you to Merapi.

• Merapi Guide Association (MAGIC)

  phone: +62 878 36325955

Alternatively you can hire a scooter in Yogyakarta around Rp 75,000/day and ride out to the summit. Ride north out of Yogya on Jl. Magelang for 45 min. When you reach Mungkid turn right onto Jalan Boyolali - Mungkid and head towards Ketep. At Ketep turn right and continue following the Jalan Bololali - Mungkid into Selo. From Selo ride up the steep road (on the right as you come into Selo) to the trail entrance where you can leave your scooter .

Kaliurang

Guide books in the 1960s and 1970s had regular references to Kaliurang-based guides. However, as the eruptions of the last 20 years have shot hot gases and eruptive materials in a more southward direction, Kaliurang is no longer the popular point of access it was in the 1970s and 1980s. In that era, Vogels homestay in Kaliurang was legendary for its hospitality and connection with walking up the southern slope to the peak. In the 1990s and 2000s Kaliurang has varied between being a part of a prohibited zone designated by government officials and not a very safe place to visit.

Other routes

Volcanology Observation posts existed in Dutch colonial times at Babadan (north-west slope) and more recently Plawangan (between Merapi and Kaliurang) - in most cases walking trails from the observation posts existed in the past. However due to the last 4 or 5 major eruptions, these points of access need clarification.

There are a few ojeks (motorcycle taxis) offering informal transport around the area.
In the villages around the base of Merapi, almost any vehicle you see on the road is a potential lift (for cash), so don't be shy.

Climbing Merapi

Trekking on and around Merapi is a popular activity (at least when the volcano isn't spewing out hot gas and ash). From Selo, the nearest village on the north slope, it is 3 hr hike to the summit for the fit and healthy. For others it will take mm ore than 4 hr to climb, and nearly the same time to get back down again.
Carry a small pack with some food, a good flash light, with spare batteries (available for purchase in Selo village), and at least 2.5 litres of water per person. Also make sure to bring warm clothes and jacket and perhaps gloves, since the wind and sweat can make you really cold.
The track to the top is a reasonable grade and is clearly defined and easy to follow. Once through the tree line the track is less defined and the final climb to the summit (after the memorial plaque) is a very steep scramble over loose and broken rock. While not in itself dangerous, do take your time on the last section. Recommended to use GPS-based map offline apps in your phone
like Maps.me or OSMAnd that already includes the tracks to the top of Merapi.
Most climbers start at about 00:30-01:00 to be sure of reaching the summit by sunrise at 05:30. Night climbing is wise in any case, as the upper reaches of the mountain are completely treeless and the sun can fry you to a crisp. The sunrise views across East Java are quite stunning.
Pay attention also on the way back, since the trail is extremely slippery and it's easy to fall down.

Organized trekking

Irregularly 9-km organized trekking is done along the Merapi slope with more than 1,000 participants begins and ended at tourism village Pulesari. Trekking fee is only Rp 25,000 and includes a t-shirt, meals, insurance, and lottery coupons. For further information you may ask at Sleman Culture and Tourism Agency.

Other

The less active should not feel left out as there are far less strenuous treks around the base of the mountain. Ask around in Selo.
Depending on the state of volcanic activity you may be able to witness molten lava flows way down the slopes of the mountain. Take local advice.

A signboard at the entrance of the Merapi Plateau reads:
"Leave nothing but tracks, take nothing but photographs"

Selo and the surrounding area has plenty of Warungs and Bakso carts serving delicious Indonesian Street food at very cheap prices. You will not find any upscale restaurants.

Nothing except the local stuff. Carry your own bottles, at least 2.5 liters of water, since there are no sources on the way.

Homestays

• Ratri Homestay

  phone: +62 813 29287256, +62 815 67792923, +62 878 36325955
  Clean rooms Tea or coffee is provided anytime, by request. There is a Merapi viewpoint area, and the owner can provide a transport service and organise volcano and camping trips for guests. M Sony is the owner and is also the leader of guide at Selo.

• Satria Homestay

  phone: +628 522 9577900
  Closest homestay to the New Selo sign and beginning of Merapi ascent. Rp 100,000 and 150,000 clean/basic rooms including breakfast. The manager, Wondo, is extremely friendly and helpful. Speaks good English and will escort you up Merapi for Rp 350,000 or will arrange a non-English speaking guide for 250. He also has extra warm clothing and torches if he doesn't think you're well equipped. He has more information about other "soft-trekking" opportunities around the beautiful highlands up there.
• Superman Homestay is next to Ratri Homestay.

Various other budget homestays around the area - simply ask around and you can get a room for less than Rp 30,000 per person. Consider looking for a place with hot water, since it can get chilly also in the village.

Camping

There are no explicit rules which prohibit camping on and around the mountain. You will need to bring in all your own equipment and you must keep yourself fully briefed with the latest safety reports. Also make sure you bring in enough water, as the springs and streams on the mountain are very sulphurous.

It is hard to think of many more dangerous volcanoes anywhere in the world. Always heed local advice from a guide, and it pays to check the bulletins at the Smithsonian Global Vulcanism Program and the Indonesian Geological Survey (in Indonesian) .

• Borobudur and Prambanan are two hours drive away.
• Yogyakarta is also about two hours by car.
• For more adventure, plan a climb to Mount Bromo for more active volcanoes.