Allbirds Tree Flyer 2 Review: A Sustainable Daily Trainer That Gets Close

Introduction

The Allbirds Tree Flyer 2 is the second version of the brand’s higher-performance daily trainer, and it arrives with a familiar tension: Allbirds is arguably the most sustainability-focused shoe company out there, but sustainable running shoes have historically asked runners to give something up. The first Tree Flyer surprised us by not being bad at all, with its angular, almost cybertruck-like midsole geometry, and this follow-up refines the formula while pushing the carbon footprint down even further.

Allbirds claims the production of this shoe emits 7.2 kilograms of CO2, which it says is roughly half the emissions of an average running shoe. Nearly every component involves recycled or reduced-carbon materials. That mission is genuinely backed by action rather than loose greenwashing language, and it shapes everything about how this shoe should be judged.

Who This Shoe Is For

The Tree Flyer 2 is best understood as an easy-day and gym trainer in the 3 to 5 mile range, which is where most Allbirds runners realistically log their miles. It is not a tempo weapon or a long-run specialist, and it is not trying to be. If you want a shoe that aligns with your values and still handles regular short runs comfortably, this sits at the top of the sustainably minded category.

At 10.6 ounces (301 grams) in a men’s size 9, it is about an ounce heavier than the first version and firmly in heavier daily trainer territory. It packs down nicely, though, which makes it a reasonable travel companion for hotel-gym cardio sessions.

Upper and Fit

The upper is a knit Tencel lyocell construction that wraps the foot securely with very little movement inside the shoe. Heel padding locks the ankle down, and the new external overlays, absent on the first version, add structure that was previously missing.

That structural improvement addresses one of our main complaints about the original, where the foot could slide around due to a lack of support. The knit itself feels comfortable and secure, and aesthetically the shoe looks genuinely good while keeping the clean Allbirds design language, minus the odd circular cutout from before.

Midsole and Ride

The midsole story is the most interesting part of this shoe. Allbirds uses a PEBA-based foam blended with castor bean material, aiming to keep the ride bouncy while increasing the sustainable content. The company does not disclose the exact percentage split, though similar efforts have historically landed near a 50/50 balance of sustainable versus oil-based foam.

The honest takeaway: the ride is still on the firmer side. The brand is essentially using the bounciest foam available to offset the inherent firmness of castor bean-based foam, and it does not fully translate into a plush experience. That said, it is far from the worst midsole we have run in, and it handled a six-mile test run without complaint. Stack height is 31.2mm in the heel and 23.2mm in the forefoot.

The outsole features fairly aggressive rubber lugs with solid grip, good enough that the shoe could double as a light trail option if needed.

Things to Consider Before Buying

Price is the sticking point. At $160, this sits at premium daily trainer money, and there are many conventional shoes at or below that price that outperform it as pure running tools. If you are evaluating it strictly on performance, that trade-off is hard to ignore.

There is also a philosophical question about what “sustainable” should mean: a shoe built from lower-emission materials, or a shoe built to last longer so you buy fewer of them. Durability-focused brands take the second route, and some runners will reasonably prefer that approach even with oil-based foams.

Buying Advice

If your priority is sustainability first and running performance second, the Tree Flyer 2 is the best effort we have seen from a sustainably minded company, and it earns genuine credit for that. As a pure performance purchase, it lands in yellow-to-orange territory because of the price and the firm ride.

Buy it if you run 3 to 5 easy miles at a time, want a gym and travel-friendly trainer, and care about where your shoe’s materials come from. Skip it if you want maximum performance or value per dollar, because conventional trainers at lower prices beat it on both counts.

Conclusion

The Allbirds Tree Flyer 2 is a well-made, good-looking daily trainer that halves the carbon footprint of a typical running shoe while remaining genuinely runnable. The ride is firmer than its $160 price suggests, and it is heavier than most of its competition, but as a statement of what sustainable running shoes can be, it is the strongest effort yet. For the right runner, the trade-off makes sense.