Canadian ultramarathoner Stephanie Case is the 1st woman to run 100 miles in Antarctica

She admits the race — in which she ran a 4.2 kilometre loop 38 times over 17 hours on the coldest and windiest continent on the planet — had her rethinking her life choices at times.

But Canadian ultramarathoner Stephanie Case still bested the Antarctic Ice Ultra in Queen Maud Land, Eastern Antarctica, on Sunday. That makes her the first woman to run 100 miles, or 160.9 kilometres, on the southernmost continent covered by the largest ice sheet in the world.

She carried a Canadian flag and cried happy tears as she crossed the finish line in 17:31:39. Her running shoes crunched and squeaked through the frigid packed snow.

“I knew roughly what I would be facing, but I had never experienced an environment as extreme as that before,” Case, 44, told CBC News Monday.

“It feels pretty amazing to put women on the map there, especially in a place that used to be called the womanless continent.” 

Organizers call it the “ultimate test of human endurance at the bottom of the world.” Runners have been braving icy temperatures in the Antarctic Ice Ultra since its inaugural race in 2024.

For safety reasons, the course is a 4.2-kilometre looped circuit around a basecamp — meaning those who completed the 100-mile ultramarathon ran the same loop 38 times plus another 300 metres.

Stephanie Case during the Antarctic Ice Ultra on Sunday. (Jan Lenfert/Peak Pixel Cafe/The North Face)

Case says she got into a rhythm, focusing on 10 loops at a time to make it a full marathon before stopping to warm up in the aid tent. Although on the first round, she had to stop after eight loops because her balaclava had iced up so much she couldn’t breathe through it.

They also had to start racing at 1 a.m., the coldest part of the night, due to incoming storms, Case said.

Race organizers described Case’s time as “blazing fast” in an Instagram post, adding it was “an extraordinary display of speed, strength and endurance in one of the most extreme environments on Earth.”

She placed second overall out of 28 runners. Yusheng Ni of China won the race, finishing in 17:02:24.

Stephanie Case just after crossing the finish line. (Jan Lenfert/Peak Pixel Cafe/The North Face)

‘Motherhood isn’t the finish line’

This isn’t the first time Case, 44, a former UN human rights lawyer who was born in Kingston, Ont., has made global headlines for smashing gruelling races.

In May 2025, Case won the Ultra-Trail Snowdonia in Wales, where she placed first among women with a time of 16:53:22 and went viral for the race photos where she breastfeeds her daughter, Pepper, who was six months old at the time.

Some of the attention was negative, Case says, explaining there were people who said she should be at home with her baby, and that she was selfish for training with a young daughter.

“I think that is completely the wrong narrative,” Case said.

“Moms shouldn’t feel guilty for prioritizing things that make them feel happy and whole — it makes us better parents in the end.”

Ultrarunner Stephanie Case is pictured during the Ultra-Trail Snowdonia in Wales, where she came in first, on May 17, 2025. (Stephanie Case)

Now, Case says she’s excited to go home to Chamonix, France, and tell Pepper all about her race. Pepper also watched her finish on the livestream, she added.

“I hope this shows everyone that motherhood isn’t the finish line,” she said.

“I was racing to prove to myself, and to anyone out there, that moms can do pretty badass things.”

Next up for Case is the Arctic Spine, a 472-kilometre trail race in northern Sweden in February. She noted she will need to go on skis, pull her own sled, melt her own snow and pitch her own tent. And she joked that the extreme conditions in the Antarctic Race Ultra had her questioning her decision to sign up for her upcoming expedition through the Arctic tundra.

“I was rethinking my life choices out there during the race in Antarctica, I must say.” 

Stephanie Case pictured during the the Antarctic Ice Ultra on Sunday. (Antarctica Ice Ultra/Runbuk)