When Sim Phei Sunn was a schoolgirl, she did not fare well in her physical proficiency tests. While she played racket games, cycled and swam, she did not consider herself to be good at sports.

But Phei Sunn turned out to be a late bloomer. On 27 July 2023, when she was 47, Phei Sunn scaled K2, the second highest mountain in the world. Known as ‘The Savage Mountain’, K2 is arguably a much more difficult climb than Everest, the highest mountain.

She was one of two women from Singapore who made it that day to the top of K2, which is 8,611 metres high. They were the first Singaporean women to summit both K2 and Everest.

Phei Sunn not only climbs mountains; she is also an avid ultramarathon runner. In 2003, she took part in her first full marathon, and in 2007, she had completed her first ultra-marathon. Today, she participates in ultra-events every few months, typically covering distances from 100km to 100 miles in the mountains. The longest run she has done is 200 miles (322 km) in Singapore during the Covid pandemic when she could not travel.

Phei Sunn’s journey from being a non-sporty student to climbing the world’s tallest mountains and completing ultra-marathons began when she was an undergraduate and started running to lose weight. Her first run was just 3 to 4 km, and it took her a long time to finish. Gradually her fitness grew, the distances got longer, and Phei Sunn discovered she was really good at endurance.

Her interest in mountaineering began with the Singapore Women’s Everest Team’s call for participants in 2004. While she did not get selected for the team that eventually summited in 2009, it ignited her dream of climbing Mt. Everest.

This dream became a reality on May 22, 2019, when she scaled the world’s highest mountain. In December 2021 she summited Mt. Vinson in Antarctica, and in doing so she secured her place in local mountaineering history by having climbed the Seven Summits – the highest peaks on each of the seven continents.

Mountain-climbing was not all smooth-sailing for Phei Sunn. There was a period of seven to eight years when failed summit attempts led to a lot of self-doubt. This was when she began taking part in Ironman triathlons and ultra-trail running. It was a move that, she realised later, strengthened her not just physically but also mentally. The two sports – mountaineering and trail running – are complementary.

Her ultra trail races take anything from 20 plus to 40 plus hours. Knowing that she can keep going for such lengths of time gives her the assurance that she can handle the long summit pushes and descents. Meanwhile, successfully navigating the often-treacherous terrains of mountains gives her the confidence to tackle more technical trail routes.

“Both,” she said, “are about endurance (my strength) and spending a long time in the mountains (my joy).”

Even when she was doubting herself as a mountaineer, climbing Everest was always on her mind. It was, she said, a motivational mantra for everything she did. When she finally succeeded in 2019, the reality of it only hit when she had returned to base camp.

“An immense sense of mixed emotions – relief, disbelief, elation, and sadness – washed over me all at once. It was a chapter that I then took a few months to slowly savour and process,” she said in an interview after her climb.

Scaling K2 then became the next challenge. “K2 is such a legendary and treacherous peak that climbers speak with great deference about. When I began climbing, I never imagined that I would even attempt this, let alone summit,” she said.

In July 2023, there was only a very small weather window for climbing K2. Many climbers set off from Base Camp where the chances of making it to the top fluctuated with the unstable weather and an impending worsening snow and wind. Taking advantage of a tight opportunity, climbers lined the dangerous Bottleneck to be in position for the summit attempt. On 27 July 2023, the weather cleared, and Phei Sunn was able to push on and reach the summit.

While she is mindful of her age ticking by, Phei Sunn is looking forward to many more climbs: “There are so many mountains in the world; terrains that I am not familiar with, places that I have not been to, techniques that I have not tried. Mixing up any of these combinations would throw up endless interesting challenges. My plan is simply to stay active and open to possibilities, see what captures my imagination, and try to make it happen.”

When Sim Phei Sunn was a schoolgirl, she did not fare well in her physical proficiency tests. While she played racket games, cycled and swam, she did not consider herself to be good at sports.

But Phei Sunn turned out to be a late bloomer. On 27 July 2023, when she was 47, Phei Sunn scaled K2, the second highest mountain in the world. Known as ‘The Savage Mountain’, K2 is arguably a much more difficult climb than Everest, the highest mountain.

She was one of two women from Singapore who made it that day to the top of K2, which is 8,611 metres high. They were the first Singaporean women to summit both K2 and Everest.

Phei Sunn not only climbs mountains; she is also an avid ultramarathon runner. In 2003, she took part in her first full marathon, and in 2007, she had completed her first ultra-marathon. Today, she participates in ultra-events every few months, typically covering distances from 100km to 100 miles in the mountains. The longest run she has done is 200 miles (322 km) in Singapore during the Covid pandemic when she could not travel.

Phei Sunn’s journey from being a non-sporty student to climbing the world’s tallest mountains and completing ultra-marathons began when she was an undergraduate and started running to lose weight. Her first run was just 3 to 4 km, and it took her a long time to finish. Gradually her fitness grew, the distances got longer, and Phei Sunn discovered she was really good at endurance.

Her interest in mountaineering began with the Singapore Women’s Everest Team’s call for participants in 2004. While she did not get selected for the team that eventually summited in 2009, it ignited her dream of climbing Mt. Everest.

This dream became a reality on May 22, 2019, when she scaled the world’s highest mountain. In December 2021 she summited Mt. Vinson in Antarctica, and in doing so she secured her place in local mountaineering history by having climbed the Seven Summits – the highest peaks on each of the seven continents.

Mountain-climbing was not all smooth-sailing for Phei Sunn. There was a period of seven to eight years when failed summit attempts led to a lot of self-doubt. This was when she began taking part in Ironman triathlons and ultra-trail running. It was a move that, she realised later, strengthened her not just physically but also mentally. The two sports – mountaineering and trail running – are complementary.

Her ultra trail races take anything from 20 plus to 40 plus hours. Knowing that she can keep going for such lengths of time gives her the assurance that she can handle the long summit pushes and descents. Meanwhile, successfully navigating the often-treacherous terrains of mountains gives her the confidence to tackle more technical trail routes.

“Both,” she said, “are about endurance (my strength) and spending a long time in the mountains (my joy).”

Even when she was doubting herself as a mountaineer, climbing Everest was always on her mind. It was, she said, a motivational mantra for everything she did. When she finally succeeded in 2019, the reality of it only hit when she had returned to base camp.

“An immense sense of mixed emotions – relief, disbelief, elation, and sadness – washed over me all at once. It was a chapter that I then took a few months to slowly savour and process,” she said in an interview after her climb.

Scaling K2 then became the next challenge. “K2 is such a legendary and treacherous peak that climbers speak with great deference about. When I began climbing, I never imagined that I would even attempt this, let alone summit,” she said.

In July 2023, there was only a very small weather window for climbing K2. Many climbers set off from Base Camp where the chances of making it to the top fluctuated with the unstable weather and an impending worsening snow and wind. Taking advantage of a tight opportunity, climbers lined the dangerous Bottleneck to be in position for the summit attempt. On 27 July 2023, the weather cleared, and Phei Sunn was able to push on and reach the summit.

While she is mindful of her age ticking by, Phei Sunn is looking forward to many more climbs: “There are so many mountains in the world; terrains that I am not familiar with, places that I have not been to, techniques that I have not tried. Mixing up any of these combinations would throw up endless interesting challenges. My plan is simply to stay active and open to possibilities, see what captures my imagination, and try to make it happen.”