The New King of the Trail? A First Look at the Nike ACG Ultrafly

An all new trail shoe is here from Nike, and it's a departure from the usual trail lineup. Developing the new ACG Ultrafly was a demanding, two year process. During this time, the shoe underwent over 30,000 miles of rigorous testing across seven countries and 25 US states. It's a shoe that marries Nike's expertise in running with the outdoor knowledge of the All Conditions Gear (ACG) division.

The ACG Ultrafly was created for athletes who embrace the outdoors. It's a shoe built to move with the terrain, offering stability, traction, durability, and comfort when the trail gets rough. In the words of Brenden McAleese, Director of Nike ACG Footwear, athletes were directly involved in the shoe's development. "From the beginning, the Nike ACG Ultrafly was developed in lockstep with our Nike athletes who desired a trail tuned super shoe," McAleese said in the press release.

Nike packed the ACG Ultrafly with the most advanced footwear technology, tailoring it to meet the specific needs of athletes at every level who enjoy the outdoors. The shoe features Nike's ZoomX foam, a ZoomX sock liner, and a carbon fibre FlyPlate. The ZoomX midsole is Nike’s lightest, softest, and most responsive foam, and it gives you back 85% of your energy. In the ACG Ultrafly, the midsole is exposed, allowing it to adapt to the ground beneath you.

The redesigned FlyPlate is less rigid than its road counterpart, with a spine split that allows for more flex. This enables the shoe to contour over roots, rocks, and uneven ground, reducing strain on the athlete over long distances. The ACG Ultrafly also features a Vibram Litebase outsole for superior grip and control on various types of terrain, from steep climbs to fast descents. An upper that drains water quickly and is more breathable allows runners to handle water crossings without slowing down.

Prior to his race at Western States, Nike athlete and All Conditions Racing Department member Shea Aquilano tested a prototype of the shoe. "Before Western States, I was planning on wearing the original Ultrafly, but when I received the ACG Ultrafly about two weeks before the race, I put them on and immediately wanted to wear them," Aquilano said in the press release.

In a recent victory at the Western States Endurance Run, Caleb Olson, also a member of the All Conditions Racing Department, wore a prototype of the ACG Ultrafly. "It’s been my go-to, do-it-all racing shoe," Olson said.

Beyond the technology, the shoe has an improved fit. Runners can confidently tackle difficult terrain thanks to a wider forefoot and heel, while the redesigned upper, trail specific last, and a more generous toe box ensure lasting comfort mile after mile.

Expect the ACG Ultrafly to be released in the spring of 2026. Hit the ‘Notify me’ button and we’ll inform you as soon as these are available to purchase.