Nike Unleashes the ACG Ultrafly: A Trail-Tuned Super Shoe Built for Athletes Who Choose Wild

Nike is unveiling the ACG Ultrafly: a trail-tuned super shoe purpose-built to move with the terrain, delivering ever-ready stability, traction, durability and comfort, even when the miles stop playing nice. The shoe is built to power every step forward and instill confidence for the athlete who chooses wild. 

Developed through 13 rounds of testing encompassing more than 30,000 miles, the ACG Ultrafly combines the outdoor-specific expertise of ACG with Nike’s unparalleled running DNA. The result: a trail-tuned super shoe engineered for optimal performance and agility in the most demanding environments — serving as a testament to Nike’s relentless drive to elevate the performance of all athletes, wherever they compete.

“From the beginning, the Nike ACG Ultrafly was developed in lockstep with our Nike athletes who desired a trail-tuned super shoe,” says Brenden McAleese, Director, Nike ACG Footwear. “They pushed us to rethink what fit, form and feel could be for a trail shoe, and every design decision was informed by their feedback and validated in the wild. This shoe isn’t just inspired by the terrain. It’s engineered to redefine how fast you can move with it.”

The ACG Ultrafly incorporates Nike’s most advanced footwear technology, tuned specifically to the needs of elite and everyday outdoor athletes across all trail disciplines and all kinds of wild, from 1-kilometer vertical ascents to multi-day staged events across some of the world’s most inhospitable terrain.

This begins with Nike’s industry-leading ZoomX foam, a ZoomX sock liner and a unique carbon fiber FlyPlate, which combine to enable phenomenal propulsion and a consistent, responsive ride.

The ZoomX midsole is comprised of Nike’s lightest, softest and most responsive foam, which provides 85 percent energy return and enhanced impact protection — and is exposed in the ACG Ultrafly to allow the midsole to morph as needed to fully respond to the terrain.

The redesigned FlyPlate is less rigid than its Nike Ultrafly predecessor, with a spine split that enables flex to carve over roots, rocks and difficult terrain, helping athletes run longer without perceiving as much strain, with unmatched torsional flexibility and support, mile after mile.

A Vibram Lightbase outsole provides superior grip, reduced weight and next-level control on rugged uphill and downhill terrain, while a faster-draining and more breathable upper helps runners take on water crossings and other trail realities without breaking stride.

“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,” says Nike athlete Shea Aquilano, a member of the All Conditions Racing Department. “I really, really like them. They’re a good blend of responsiveness and cushioning, and the breathability and ability to drain water really helped me feel dry and like my legs weren’t getting beat up over the course of a long race.”

These advanced innovations, tailored to the exact needs of outdoor athletes, pair with a wider forefoot and heel that allow runners to navigate the harshest terrain with confidence. Further, the redesigned upper, trail-specific last, more accommodating toe box, internal fit band and gusseted tongue deliver an improved fit that provides consistent comfort over countless miles.

All the while, the bold design of the ACG Ultrafly embodies the audacious energy of the outdoor athlete, with proportions that stand out from the pack and a Safety Orange launch colorway that demands attention on any trail. (A prototype model and colorway is pictured here.)

“Since the beginning of 2024, I’ve been racing in the Nike ACG Ultrafly,” says Nike athlete Caleb Olson, a member of the All Conditions Racing Department who recently won the Western States Endurance Run in a prototype version of the silhouette. “It’s been my go-to, do-it-all racing shoe. It can handle some of the most rugged terrain I’ve raced on at Transgrancanaria, as well as the singletrack at Western States. It’s a great balance between all-day comfort and top-end performance that has helped put me on top of the podium at some of my biggest races.”

The ACG Ultrafly, offered in women’s and men’s sizing, was born from Nike’s unyielding commitment to listening to the voice of the athlete — answering the call for a trail-tuned super shoe equipped to address every element of trail running and racing.

The silhouette was refined over more than two years of development, which included gathering insights from wear testers across seven countries and 25 U.S. states, prototype testing during some of the world’s biggest races, and logging the most testing miles for a single product in recent Nike history.

“Nike constantly wants our feedback, with a persistent belief that better is always around the corner,” says Nike athlete Drew Holmen, a member of the All Conditions Racing Department who tested prototypes of the silhouette since its inception. “What’s the result of that? A more stable shoe. A more responsive shoe. A faster shoe. Just straight better. That’s the Nike ACG Ultrafly.”

The silhouette draws on Nike ACG’s legacy, beginning in the 1980s, of creating trail footwear that’s light, fast and speaks trail fluently — delivering audacious solutions matched only by the tenacity of the athlete who chooses wild.

The silhouette is also powered by Nike’s 50-year history as the biggest champion of runners and the running community, as well as the brand’s continued commitment to creating the most technologically advanced products to help runners across all disciplines reach their greatest potential. It joins an unparalleled lineup of trail-tuned offerings, road running footwear and racing innovations that serve the needs of all athletes, no matter where and how they choose to run.

The Nike ACG Ultrafly will be available in spring 2026 at nike.com and select retail partners.

View photos of a prototype version of the Nike ACG Ultrafly in the gallery below.