We spent 9.6 hours reading reviews from experts and users. In summary, this is what runners think:

6 reasons to buy

  • Most runners noticed the improve design, more responsive ride and softer upper unit of the newest version of the Altra Instinct.
  • The Instinct 3.5 has an improved lacing system that gained positive feedback.
  • This shoe features the Natural Ride System that promotes natural foot movements.
  • The FootPod Outsole provides a responsive ride and flexibility.
  • Some runners noticed that this version offered improved cushioning.
  • The Quick Dry Air Mesh and the seamless design of the upper makes the interior and exterior clean and non-irritating to the skin.

3 reasons not to buy

  • Some runners pointed out that the sole of this shoe was too firm.
  • Based on some reviews, the heel cup was positioned too high, causing some discomfort to the backs of their feet.
  • Others noted that the forefoot section of the Instinct 3.5 was a bit narrow.

Bottom line

The Instinct 3.5 from Altra offers a newer look, an improved upper, added cushioning and a more responsive ride. The shoe gained mix reviews from wearers but overall, it is a reliable road running shoe engineered for long-distance running and ultramarathons.


Expert Reviews

82 / 100 based on 12 expert reviews

  • 90 / 100 | Running Into Myself | Level 2 expert

    It made a more nice snug fit. I appreciated that. The toes can still splay.

  • 88 / 100 | Happy Healthy Vegan | | Level 2 expert

    They have a little more cushioning, which really is awesome. Like I side for a longer runs,now I can go and do the distance runs.

  • 80 / 100 | Runner's World | Level 5 expert

    This small update to Altra’s original model tweaked the midsole density to bring it back to the feel of the popular first version, and improved the fit of the upper, giving it more toe height, a softer, foot-hugging feel, refined overlays, and an attractive toe swirl that gives the foot-shaped forefoot a more mainstream look. 

  • 74 / 100 | Fellrnr | Level 5 expert

    The Instinct is too firmly cushioned for its weight, with similar levels of cushioning to shoes that are much lighter. 

  • 86 / 100 | Triathlete | | Level 4 expert

    "The result is a lightweight, smooth-riding shoe that is versatile enough to be durable and protective for logging long training miles but responsive and agile enough for shorter interval workouts and tempo runs.

  • 80 / 100 | Feed the Habit | | Level 3 expert

    Despite the design tweaks, there aren’t any major surprises in these update; if you liked previous versions of the Instinct or Intuition, these will continue to be a favorite. 

Become an expert

  • The lacing system in the Instinct 3.5 has been redesigned. The Instinct 3.0 had a lacing system that’s too limited and tightly woven. Now, this version gives the laces a wider space between each other, making sure that most of the topside of the foot is covered. The crisscrossing of the laces even extends near the forefoot area of the shoe, making it cover more surface area.
  • The mid-foot area has been designed to have a medium volume, but it’s a bit snugger this time around. The upper unit hugs the foot well, but it doesn’t make the fit too tight or too restrictive.
  • The FootPod Outsole still offers natural flexibility, but the material used in this outer layer is firmer and more resilient against wear and abrasion. The entire sole unit still follows the natural foot shape design that’s prevalent in Altra shoes.
  • This running shoe from Altra is easier to break in, but firmer than the previous iteration. Improved cushioning systems make sure that the platform is both resistant to breakdown and still efficient in flexible & responsive underfoot cushioning.

The Instinct 3.5 fits half-a-size smaller than the regular sizing scheme. It is advised to buy this model ½ size above the standard choice. The medium-width of the heel and mid-foot areas make the fit snug and secure, while the wider forefoot area allows natural toe splaying.

The FootPod outsole, which is the same as the Altra Instinct 4.5, was designed to mimic the natural shape of the human foot. Having such a design provides runners with a more natural ride that’s balanced and stable. Natural flexibility, freedom of movement and responsiveness are the selling points of this foot-shaped outer sole.

The A-Bound is a mid-sole compound that’s made from recycled materials. It’s environmentally friendly, but very sturdy. It protects the foot from impact and discomfort when running.

Dual-layer EVA foam is a unit that offers shock attenuation, springiness and responsive underfoot support. It’s a high quality material that doesn’t easily wear off or lose structural integrity. Runners can expect a well-protected, highly efficient ride with this in the platform.

The Natural Ride System encourages natural movement of the foot by following the shape of the foot. The forefoot area is more spacious and the rear section is snugger.

The zero-drop system makes sure that the runner achieves balance, especially when transitioning from the heel to the toe. Landing the foot on the ground ensures equal distribution of impact protection, energy and natural performance.

The Quick Dry Air Mesh provides breathable support to the runner. It’s lightweight and flexible, and it has moisture-wicking capabilities while further enhances the overall comfort.

The Heel Claw construction makes sure that the rear section of the foot stays locked down and secure. It makes it easier for runners to prevent accidental slips and shoe-removals when performing.

Next-to-foot comfort is afforded by the seamless design of the upper unit. It’s an efficient design that gets rid of irritation and discomfort when wearing the shoe. Having such a comfortable inner construction allows runners to wear the Altra Instinct 3.5 even without socks.

The 5mm-thick insoles add more cushioning. Because this shoe has a low-profile design and because it has a zero-drop platform, the additional layer helps to make the foot more comfortable even when running for longer periods of time.

Jens Jakob Andersen
Jens Jakob Andersen

Jens Jakob is a fan of short distances with a 5K PR at 15:58 minutes. Based on 35 million race results, he's among the fastest 0.2% runners. Jens Jakob previously owned a running store, when he was also a competitive runner. His work is regularly featured in The New York Times, Washington Post, BBC and the likes as well as peer-reviewed journals. Finally, he has been a guest on +30 podcasts on running.