Canadian ultrarunner Stephanie Case has become the first woman in history to complete a 100-mile race in Antarctica.

Case finished the Antarctic Ice Ultra in Queen Maud Land, East Antarctica, in 17 hours, 31 minutes and 39 seconds, placing second overall in a field of 28 runners across the event's distances.

A brutal course in extreme cold

The race is built around 38 laps of a 4.2-kilometre loop around a remote base camp in the Schirmacher Oasis. Temperatures during this year's race fell to minus 35 degrees Celsius, the lowest the organisers say they have ever recorded.

Case was one of three women on the start line and the only one to finish. Until this year, the 100-mile distance had only ever been attempted by men.

Second overall behind a record winner

China's Yusheng Ni won the race in 17 hours, 2 minutes and 24 seconds, beating his own course record by more than five and a half hours. Both runners smashed the previous mark of 22 hours, 40 minutes and 47 seconds, which Ni set in 2025.

Case, a human rights lawyer from Kingston, Ontario, who now lives in Chamonix, France, crossed the finish line carrying a Canadian flag. She had chased Ni for much of the race, at times running within a minute of the eventual winner.

The race began at 1 a.m. to dodge the worst of the storms, and runners battled fierce winds throughout. Case, a former United Nations human rights lawyer, said she had a sense of what the conditions might demand but had never run in an environment that extreme.

Motherhood is not the finish line

Speaking to BBC Sport after the race, Case said she wanted to prove to mothers everywhere that motherhood is not the finish line and that they can go out and pursue big adventures and dream big.

Case gained international attention last year when she won the Ultra-Trail Snowdonia ultramarathon in Wales while breastfeeding her six-month-old daughter Pepper at rest stations along the route.

She is the founder of Free to Run, an organisation supporting women and girls through running, and she now plans to take on the 472-kilometre Arctic Spine race in Sweden.

The Antarctic Ice Ultra began in 2024 and offers distances from a half-marathon to 100 miles, along with a 24-hour relay. Case is now the event's first women's 100-mile finisher — and its inaugural women's record holder.