Stephanie Case Becomes the First Woman to Run 100 Miles in Antarctica

Stephanie Case has become the first woman to finish 100 miles in Antarctica, completing the Antarctic Ice Ultra in Queen Maud Land in an official time of 17:31:39. Race organizers announced the result on Instagram and logged it as the continent’s first women’s record at the distance, a slot that had read “vacant” on the event’s record list going into the race.

Case had flown south with a bigger target in mind. Her entry on the race’s own competitor page said she planned to go after the overall 100-mile record, and she finished second overall to Yusheng Ni of China. Ni won the race in 17:02:24, only 29 minutes and 15 seconds ahead of her, and took more than five and a half hours off the continental record he set at the same race in 2025.

That 2025 mark was 22:40:47, which means Case’s run on its own would have beaten it by more than five hours. The record has fallen at every edition since the race started in 2024, when Americans Paul Johnson and Roberto Sembiante shared the first mark of 23:22:57. Ni also holds the Antarctic 100K record of 9:20:28, set at the Antarctic Ice Marathon’s 100K race in 2024, and has now lowered the 100-mile mark two years running.

A Race at 70 Degrees South

This was only the third edition of the Antarctic Ice Ultra, which is run out of the Ultima camp in Queen Maud Land, East Antarctica, at around 70 degrees south. Runners get 24 hours of daylight and distances ranging from 50K up to 100 miles, and the organizers list wind chill as low as -35 C (-31 F) among the conditions entrants should expect. The event is organized by Runbuk, the company behind the 777 World Marathon Challenge, whose seven marathons on seven continents also begin on the ice.

The Antarctic Ice Ultra is a separate event from the longer-running Antarctic Ice Marathon on Union Glacier, where Australia’s Catherine Drysdale became the first woman to win outright last December in 3:48:43. Both belong on any list of the hardest races in the world, and women have now made history at one or the other in back-to-back seasons.

Case spent the night before her cargo flight from Cape Town working through what she did not yet know about racing in that kind of cold. In a post on her own Instagram, she listed the questions on her mind, from cold fingers to an upset stomach. “How will my lungs deal with the dryness of the air?” she wrote. “How will I prevent myself from sweating when I run (an absolute no-no in these conditions).”

From Aid Work to the Ice

Case spent years as a human rights lawyer in conflict zones, with postings for the United Nations and aid groups in Afghanistan, South Sudan and Gaza. She also founded Free to Run, which brings running and leadership programs to women and girls in war-affected regions. On the trails, she has raced the 450K Tor des Glaciers, a nonstop race through the Alps in which runners find their own way, and she won the 100K at Ultra-Trail Snowdonia in May 2025, six months after her daughter was born, nursing her at aid stations along the course.

She left the UN and signed a professional contract with The North Face in October 2025, as journalist Anne-Marije Rook reported ahead of the race, and she now lives and trains in Chamonix, France. The women’s line on the Antarctic record board, blank until this weekend, now carries her name and a time of 17:31:39.