Nike ACG Ultrafly

ACG Ultrafly

In 2021, Nike initiated a project to design a rapid trail shoe to augment its modern collection of off-road running footwear. Two years later, following rigorous testing across thousands of miles and some of the most demanding ultramarathons, the brand launched the Nike Ultrafly – a cutting-edge trail runner designed for racing.

Released in 2023, the original Ultrafly broke new ground in multiple ways. Inspired by Nike’s super shoes, it features full-length ZoomX foam in a fabric-wrapped, cross-rockered midsole, with a springy, fork-shaped carbon fiber plate in the midfoot for an outstanding balance of cushioning, stability and energy return in a lightweight package. Its outsole is made of Vibram’s high-performing Megagrip compound – a first for Nike’s trail shoes – with a specially designed tread pattern incorporating both Litebase and Traction Lug technologies to provide lightweight agility and unrivaled traction across varied terrain. The Ultrafly’s lightweight upper is a thin layer of breathable Vaporweave mesh with a sturdy lace structure, plush collar and firm heel counter that combine to produce reliable lockdown for traversing challenging landscapes.

In 2025, Nike announced its first Ultrafly update, due for release in spring 2026. Called the Nike ACG Ultrafly in reference to the brand’s long-running All Conditions Gear sub-label, it was tested over 13 separate phases, taking in over 30,000 miles of running. It retains the propulsive FlyPlate, responsive ZoomX foam and grippy Vibram Litebase outsole of its predecessor, but its midsole has shed its fabric wrap so as to respond better to the environment, while its carbon fiber plate is more malleable and has a split down the center that reduces strain by facilitating better flexion of the foot over rocks and roots. Designed around a brand new last, its upper is tuned precisely for the trails, with a more accommodating fit, a more breathable and better-draining mesh, and an internal fit band and gusseted tongue for more secure lockdown. Meanwhile, swooping topographical design lines and exaggerated Swooshes give it a striking esthetic.

Elite athletes have helped shape the trajectory of the Nike Ultrafly, beginning with American ultrarunner Tyler Green, who tested it over 1000 miles and competed in it at events like the 100-mile Western States Endurance Run, where prototype versions took him to two runners-up medals between 2021 and 2023. Female ultra runners like Brittany Peterson and Nienke Brinkman also trail-tested the Ultrafly, Brinkman describing it as the “perfect racing shoe… on fast courses.” Meanwhile, members of Nike’s All Conditions Racing Department like Shea Aquilano praised the Ultrafly ACG, hailing its “blend of responsiveness and cushioning” as well as its “breathability and ability to drain water”. In 2025, American trail runner Caleb Olson took first place in an ACG Ultrafly prototype, showcasing its ability to conquer the most challenging of trails.

Described by Nike as “A Trail-Tuned Super Shoe”, the Ultrafly is an advanced running silhouette built to power elite athletes and amateur runners across the trails at top speed, in maximum comfort with the utmost style.