Bromo Tengger Semeru 100km Ultra: Above Caldera And Beyond Sand  

BTS Ultra
BTS Ultra 2017

NOTE: This is a longer version of the article published in Run SG magazine Feb & March 2018 isssue for the race participated in Java island – 2017 BTS Ultra.

Bromo Tengger Semeru (BTS)

The race as it name suggest took place in Bromo Tenger Semeru National Park in East Java, Indonesia at various altitude and landscapes. The 100km race attracted runners to experience route of Mount Bromo active volcano, Mount Batok and Mount Pananjakan. The race did not take runners to summit Mount Semeru (the highest mountain in Java) – given its very active volcanic state that erupts periodically but it brought runners to its stunning savannah basecamp area.

Active volcano – Bromo Tengger Semeru National Park view from Cemoro Lawang

Cemoro Lawang and Tengger Caldera

It’s hard to explain the first moment when I laid eyes on groups of rugged volcanoes surrounded by a vast greyish floor of sand and ashes as I stood at the edge of Cemoro Lawang viewpoint of Tengger Caldera after being dropped off by our shuttle from Surabaya. The entire complex was a result of the massif and grand eruptions of ancient Tengger volcano. This is where the Tenggerese ethnic reside, who believe their Hindu Gods dwelled in the mountain as guardian and protector.

Aside of tourists, for few days this area was crowded with runners and volunteers – a unique setting where our race administration took place from identity verification, sign-up waiver form, mandatory gear check, race bib collection and deposit drop bags. Race briefing was presented live while runners still queuing. The atmosphere was buzzing (though at some point felt a bit disorganized) but thanks to live music performance and the well-known Reog traditional dance, we were entertained by rich Javanese heritage which the island is well known for. After a few bowls of delicious rawon (rice with soup dish) served at the race briefing, I made my way to our hostel to get some rest and get ready for the 100km race.

Reog Ponorogo traditional dance with largest mask in the world made of tiger skin and peacock feathers.

Meal to enjoy, pre-race BTS Ultra waiting for rawon soup to be served.

The 2017 BTS Race Experience                                                                       

  • Ranu Pane

The race started on 4th November midnight at Cemoro Lawang. The plan was to stick running along with my partner, Mr E – something I hardly do as I prefer running solo. A steep climb follows in the first 7km after we ran across the sand of sand. I waited for my partner to arrive in Ranu Pane before we continued to Ranu Kumbulo. Hover over images below for description.

  • Ranu Kumbulo 2,400m

I shuffled along forest route from Ranu Pane as the sun began illuminating the trees. Few runners stop for a quick rest at the hiking huts but I continued to run. About 6 am I reached the beautiful Ranu Kumbolo lake in the middle of mountain areas – it was a good refreshment for soul, mind and leg. Cool mountain air freshened the morning. This area was busy with hikers who camped there to climb Mount Semeru. My partner arrived not long after.

Ranu Kumbolo lake


  • Kalimati 2,700m

The next path was a few short climbs before reaching a flat area of tall grassland and prairie with a distant magnificent view of the Mount Semeru. This reminded me of Mount Kilimanjaro in Tanzania. A bit sunny here and felt warm – some runners stop to buy some fruits from a local vendor. From Kalimati we ran through the same route back to Ranu Kumbolo and enjoyed the backdrop of the stunning blue calm lake.

Majestic Mount Semeru as seen on the way to Kalimati
Runing down to camping ground of Ranu Kumbolo


  • Jemplang 2400m via Mount Ayek Ayek

I hiked up toward next hill after a flat section of savannah golden grass. It took longer than expected to reach Jemplang despite running most of the downhill, flat village road and forest trail. The slowest section was the steep descent with rope assistance around Mount Ayek-Ayek which proved to be the bottleneck. I must have injured my right shoulder from this steep descent as I slide down. Finally, after the never-ending slow gradual road, I reached Jemplang an hour before the cut-off of 2 pm. As much as I wanted to continue after a quick pit-stop, I waited for my partner to arrive.

  • Bromo 2,250m

Along the flat road of green valley, the view was beautiful like New Zealand (I once lived for more than a decade) – minus herd of sheep but a group of motorcyclists were plenty. It was about to drizzle and wind blowing so I put on the rain jacket.

Not look after, the paradise zone changed drastically to moonscape and desert view. I hiked the sea of sand followed by an ascent on crevasses made of hard sand and ashes. Hover over images below for description.

As I got nearer, the scary sound from Bromo volcano was much louder. I reached Bromo crater just before sunset after climbing about 250 steps.

This is Bromo crater with white smoke emanating
Bromo crater path that required runner to complete of about 9km loop comprising of some exposed section, and narrow trail.
  • Batok 2,250m

As it got darker, the traverse along the narrow ridge of crater got slower. Two other runners agreed to tag along. The wind blew constantly and it got chillier. We called the race organizer to check on our path as doubt arose from one of other runner, instead we were convinced on the right path we were on. Roughly 9km of crater loop made and then the most difficult part was to come down via canyon of Mount Widodaren as it was steep with loose rock. This was followed by a series of bamboo stairs to descent along a beautiful sacred canyon before finally reaching Batok (W7).

I retired here around 5 am, another 20km to go for an ascent to Mount Batok 2,250m and Mount Penanjakan 2,770m which I did not believe at the time the 8 am cut-off can be met. The mountain spirit was not strong with me on the day though my legs were fine. I chose to listen to my intuition as my brain convinced me to stop after having pushed on some pretty stressful and dangerous stuff. I also took too much time from Bromo to Batok checkpoint which didn’t help with time plan.

There will be another race for me. Sadly not for fellow Indonesian runner, Andi Nursaiful (48-year-old man) who was found unconscious while racing in the 70km category. Rest in peace, brother.

Tips and What I’ll Do Differently:

  1. This race is not for faint-hearted due to element of risks involved therefore require high commitment and iron grit of determination. Some of the pain points and high safety alert were the narrow craters, steep descent using rope, and deep canyon descent.
  2.  Study course and plan race carefully. View YouTube videos to have some sense of the varied landscape.
  3. Aim to reach Batok checkpoint before dark to have day view on top of Bromo crater and not getting too slow on narrow crater course during the dark. This would mean a quicker first half of the race.
  4. Incorporate more conditioning and strength training on top of usual run mileage and stairs training.
  5. Gaiters are highly recommended especially on the sandy course in the second half of race.
  6. Wear Buff or multi headwear to protect from the dusty environment which can get into eyes and nose. Expect black sand trapped under nails for a few days.
  7. Jemplang (W5) was crowded. If need some rest and quick shut-eye this can be done by the roadside along green valley just after the checkpoint.
  8. For windy condition when on top of the calderas or peaks and chilly night, wear sufficient layers and keep moving on to avoid cold.
  9. Running with someone else requires some compromise – such as waiting for someone during a race. Need to draw some boundary so running solo is possible when is needed and follow strict time plan.
  10. As for travel tip, a backpack is more suitable than carry-on luggage due to sandy surrounding

Do Again?

Vincent Chalias, the French runner (whom I met at Ijen race) came in third overall, said to me after award ceremony that the remaining 20km was straight forward and not too technical. 

I would love to return with a stronger race plan to nail this because I believe it’s possible and therefore I can. Plus there’s so much to see and do on this magical one-of-a-kind destination.

Leaving the national park on Sunday afternoon as the rain started pouring, roads were flooded and our footprints on the sand vanished. 

Sign Up And Accommodation:

Sign up at at once it’s open for registration for 30km, 70km, 102km and 170km distance. Book accommodation early to ensure a close stay to finish/start line. Lava View Hotel is the best option given it’s the race briefing location, but there are other homestays nearby. I stayed in Losmen Adas not far away from the town centre and start/finish line.

Getting There:

Fly to Surabaya with Air Asia or Scoot from Singapore. Race organizer organised a shuttle pick-up ($16 one way) from/to the airport and journey took 3-4 hours.

BTS Ultra 80km under belt though with some unfinished business. Mr E posed against backdrop of the national park.

Are you racing this awesome course this weekend? Or have you nailed it? How many times you’ve returned to this amazing location?

Live to thrive,


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