TransJeju by UTMB 2025

There's a funny thing about pushing your limits: the moment you cross a finish line, part of you vows "never again." But then, a stubborn whisper begins, a quiet pull towards the next impossible dream.


TransJeju by UTMB 2025


After BDG Ultra 100K, my body definitely screamed for a proper break. Five weeks went by, letting my muscles heal and my mind catch up to the wild idea of doing it all again. The sharp pain from that first race slowly softened into a familiar ache, almost like an old friend I hadn't truly said goodbye to. My brain was perfectly content dreaming of endless naps, and my legs, after their strong protests, were finally considering working again. I was a 100K finisher, a title I felt both proud of and a little confused by. Honestly, I thought more rest was next, not another super long run.


But then, Trans Jeju started calling. This wasn't just "another" race to tick off my crazy list. This was personal. Korea. Ah, Korea. It's a country I deeply love, full of memories from my KAIST days in Seoul. Running here, after so long, felt like coming home, even if I'd never been to Jeju Island before.


Beyond my feelings for Korea, there was the dream. This would be my very first UTMB World Series event. If you know anything about trail running, you've probably heard of Chamonix and Mont Blanc. Running 100 miles there is my biggest dream, my ultimate goal. Trans Jeju was the important first step, exciting and a little scary, towards that dream. My tired legs, bless them, were already complaining about my big plans. But my heart was set.


Hello, Jeju!

The lessons from BDG Ultra were my best guide: how to pace myself, how important nutrition and hydration are, and how to keep my mind strong. These quiet truths I carried with me into this new adventure.


I arrived at Jeju Island on Thursday, giving me a crucial night of proper sleep. This was a true blessing, as Friday night (D-1) for a big race like this usually brings me a symphony of nerves and very little actual sleep. My friends, Ramsky and Fathan, joined me on Friday, their arrival adding an extra layer of excitement to the calm before the storm. They signed up for the 20K, their very first trail race! Seeing their excitement for their "first time" was a great boost for me, even though my "first time" was just five weeks ago, and this was way longer.


TransJeju with Ramsky & Fathan


Knowing my body was still recovering, I knew I needed the best gears. My trusty Amazfit T-Rex 3 Pro was ready to track every step and important number. My ASICS Gel Trabuco 13 gave my tired feet the grip and soft landing they needed. I knew it would be a long night, so my reliable Nitecore UT27 headlamp and power bank were packed – getting lost in the dark is never fun. And feeling good in my LICA custom jersey always helps, even if I was secretly still wondering what I'd gotten myself into.


Team Amazfit Indonesia


Arriving in Jeju, an island I'd always dreamed of seeing, felt like stepping into a beautiful picture. The air was fresh, the scenery amazing, and the UTMB event had a special energy.


Race Day Dawn: Up Hallasan We Go

Race day: Saturday, October 18th, 2025. At 5 AM, the Jeju World Cup Stadium buzzed with nervous excitement. This was it: a 100K race, "Zero to Summit," meaning we'd go all the way up Mt. Halla, South Korea's highest mountain. Eight checkpoints waited for us, like small lights guiding the way.


Start of Trans Jeju 100K


From the very start, maybe it was the rush of being in a new race, I found a good rhythm. Going through CP 1 Healing Forest (at 7 km) and CP 2 Yeongsil Entrance (at 20 km), heading towards CP 3 Eorimok Entrance (at 28 km) with its big climb, I felt strong. I even passed 142 other runners! It felt really good, a small sign that my legs hadn't totally given up.


The trails themselves were beautiful, winding through volcanic forests and offering views of the coast. They were also very well-kept, almost polished, showing the high standard of a UTMB race. But what really surprised me was Mt. Hallasan itself. I expected wild, untouched nature, like the mountains back in Indonesia. Instead, Hallasan was well-developed, with clear paths and good facilities. It was a different kind of challenge, a beautifully organized one, unlike the raw wilderness I was used to. Both kinds of mountains are tough, but in their own ways.


Trans Jeju 100K


The next part of the race, from CP 3 to CP 4 Gwanumsa Entrance (at 41 km), was a long, tough 12 km stretch of road. This is where my early speed met reality. Many runners, who seemed to have a higher VO2max (meaning they could run faster with less effort), quickly passed me. It was a humble reminder that even with a strong will, some people just naturally have more speed, and my personal speed setting was currently "sloth on a sabbatical."


The Mountain's Tough Embrace

The hardest part, the real test, was between CP 4 and CP 5 Seongpanak Entrance (at 59 km). This was the climb to the very top of Mt. Hallasan. My pace became very, very slow. Each step was a painful fight against gravity and my tired muscles. Then, a new challenge arose: a surprising, almost sharp pain in my inner thigh or groin. I realized it was the relentless, long stairs uphill, a kind of sustained climb I'd never truly encountered in any mountains back in Indonesia. This was a different beast entirely. Reaching the summit, the highest point in South Korea, felt less like winning and more like barely surviving a huge offering to the mountain gods.


Running to Mt. Hallasan


Speaking of things that were less than glorious, CP 6 Eseungak Oreum (at 71 km) had the worst toilet I have ever seen in a race. Seriously bad. But, to be fair, all the other checkpoints and even the other toilets on the mountain were surprisingly clean. A small, funny moment in the middle of all that beautiful scenery, reminding me that even in paradise, some things are just… grim.


Fighting the Dark, Chasing a Dream

It was deep in the night when my body truly wanted to give up. I even thought about having a long talk with a rock about how much my blisters hurt. My muscles were screaming, feeling like tiny, angry gnomes had been hitting them. This was a low point, a true test.


But then, a quiet whisper in my mind: 'Chamonix.' And the steady light from my Nitecore headlamp cut through the dark, showing me just enough of the path forward. The consistent numbers on my Amazfit smartwatch were like a silent coach, showing my pace, pushing me to keep going. And my ASICS-clad feet, even with all their complaints, somehow kept moving.


Then, something amazing happened. From CP 7 Camping site (at 82 km, around 11:39 PM) to CP 8 Healing Forest (at 92 km, around 2:21 AM), a sudden burst of energy hit me. This time, I had a secret weapon: energy gels with caffeine, something new I hadn't used in BDG Ultra 100K. I truly believe these little boosts helped me find a surprising second wind! With two very strong Chinese runners, we pushed hard, almost sprinting, and passed nearly 20 runners in that final section. It was exciting, a raw burst of pure energy at the very end. Perhaps it was delirium, or maybe just the sheer stubbornness of a runner who knows the finish line is there.


Crossing the Line, Carrying the Lessons

Crossing that finish line felt like a silent roar of victory from my tired body. My first UTMB race was done, and done well. The clock showed 23 hours, 37 minutes – barely, but gloriously, under the 24-hour mark! And there, waiting for me around 4:30 AM, were my friends, Ramsky and Fathan, their cheers a wonderful sound to my weary soul.


Arriving at the finish line under 24 hours


This wasn't just about the time or the distance; it was a profound victory of the spirit. Each painful step, each moment of doubt, had been a lesson, chiseling away at my perceived limits. Finishing under 24 hours and earning 3 running stones for UTMB felt like more than just a qualification; it was a tangible promise, a bold step towards that Mont Blanc dream. It proved that even when deeply tired, the mind and body can work together to achieve something truly remarkable. And perhaps the greatest, most humble victory of all? I didn't get any stomach problems (GI issues) during the race. For an ultra-runner, that's almost a miracle and shows good planning (and maybe a bit of luck!).



After the race, the best part was my mini-reunion with my old friends in Seoul. We laughed, we ate, we shared stories of volcanic trails and tired feet. This wasn't just catching up; it was a sharing of the "elixir," the wisdom and joy found in pushing beyond limits, together. That, perhaps, was the sweetest reward.


This journey through Jeju, with its beautiful mountains, its relentless challenges, and its cherished friendships, has woven itself deep into my spirit. It's taught me that life's greatest adventures truly begin just beyond our comfort zones. In those uncomfortable, vulnerable spaces, we don't just find our limits; we discover an incredible, often hidden, strength we never knew we possessed. 


My heart is already packing its tiny, bruised suitcase for BTS Ultra, ready for one final, fiery 100K dance for this year. Because the true adventure isn't just measured in miles on the trails; it's in every single challenging, beautiful step we take, pushing forward, growing, and living each day with an open, resilient heart. May we all find our own "Chamonix" – the dream that keeps our tired feet moving, one inspired step at a time.


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