Brazilian Ultrarunner Fernanda Maciel Takes More Than 13 Hours Off Salar de Uyuni Crossing Record

Maciel completed the 172.8-kilometre route from Llica to Uyuni in 19:50:08, setting a new overall fastest known time.

Brazilian ultrarunner and high-altitude athlete  Fernanda Maciel has set a new overall fastest known time (FKT) crossing the Salar de Uyuni, the world’s largest salt flat, in Bolivia. Her time of 19 hours, 50 minutes and 8 seconds is 13 hours, 14 minutes and 2 seconds faster than the previous overall benchmark of 33 hours, 4 minutes and 10 seconds, set by fellow Brazilian Valmor Giuseppe Leonardo in 2023.

The effort took Maciel across salt flats transformed by a hailstorm, through darkness and over terrain at around 3,700 metres above sea level. Here is all you need to know:

Maciel started at 5:00 a.m. on September 28, 2026, beneath the entrance/exit arch in Llica, on the western side of the Salar. She crossed approximately 145 kilometres of the salt flat before continuing for 27 kilometres along the road to Uyuni, finishing at the town’s church at 00:50 a.m. the following day.

Although the majority of the Salar de Uyuni FKT route is flat with a positive elevation gain of around 311 metres across the entire 172.8 kilometres, the route sits at approximately 3,700 metres above sea level.

Put into context, Maciel spent close to 20 hours running at an altitude close to that of the summit of Japan’s Mount Fuji, which rises to 3,776 metres.

Conditions across the Salar were significantly more complex than expected after a hailstorm transformed sections of the salt flat into shallow water and mud. Maciel also encountered numerous small holes containing water beneath the surface, forcing her to constantly adjust her foot placement and change her shoes and socks after spending time crossing little pools at kilometre 145. “I had to pay attention all the time to where I was putting my feet,” she said.

Navigation was another fundamental part of the challenge. Maciel carried her phone with the route mapped out, allowing her to follow the same trajectory used by Leonardo when he established the previous overall record in 2023. At times, Maciel had to slow her rhythm in order to navigate accurately.

The landscape became even harder to read after darkness fell. Eventually, however, the appearance of lights from hotels and houses near the edge of the desert gave her a visual reference and helped her identify the route toward Uyuni. Her strategy was simple: maintain the mapped route, adapt her speed when necessary, and avoid unnecessary stops.

The effort demanded nearly 20 hours of running across a high-altitude, exposed salt flat. The bright, open landscape added to Maciel’s exposure to the sun, while the duration of the run made managing fluid intake essential.

After the first 100 kilometres, her stomach began to struggle with food, even as her legs continued to respond well to the altitude.

Rather than following a fixed target pace, unlike in a conventional road or trail race, Maciel adapted her effort to the terrain and the demands of running at altitude. “I had to adapt my legs to a pace where my body was comfortable running 170 kilometres at altitude in a desert,” she explained.

For much of the crossing, Maciel deliberately avoided checking her watch too often. On an enormous, almost featureless landscape, the visual perspective can make it difficult to understand how much distance has been covered.

After reaching the road, she realized she had been running for 16 hours and 45 minutes and that a sub-20-hour finish was possible.

Fatigue was severe by the time Maciel reached the final road section towards Uyuni, but she continued to push, maintaining approximately 10 kilometres per hour.

“My whole body was exhausted. But I kept pushing,” she said. “It was pure mental strength. My legs were destroyed; I couldn’t open my steps. I know how to run in the mountains, but not in a flat. I didn’t have any more power, but I tried my best.” Maciel finally reached Uyuni 50 minutes after midnight on September 29, 2026, setting the elapsed record time.

Maciel has spent approximately two decades competing in ultra-distance races, but projects like the Salar crossing represent something different. “It motivates me to do tough runs outside of the competition world. These long-distance projects are completely uncertain about the result, and it scares me. I also love it, because it is something new that I have to prepare for and be connected to.”

FACT SHEET

Achievement: Official overall FKT across the Salar de Uyuni Route Llica to Uyuni, Bolivia

FKT verification: Officially confirmed via fastestknowntime.com

Total distance: 172.8 kilometres

Official time: 19:50:08

Margin to previous record: 13 hours and 14 minutes

Start: 05:00 a.m., September 28, 2026, at the Llica Welcome Arch

Finish: 00:50 a.m., September 29, 2026, at the Uyuni Cathedral

Altitude: Approximately 3,700 metres

Positive elevation gain: Approximately 311 metres

Salt-flat section: Approximately 145 kilometres

Road section: Approximately 27 kilometres

Terrain: Salt, shallow water, mud, hidden holes and road

Key challenges: Altitude, nutrition, navigation and changing surface conditions