Run and roam wild

Built for trail running and adventuring closer to nature

The Primus Trail 3.5 FG is for runners who live for the end of the road. These all-terrain trainers are light and flexible enough to move freely, and tough enough to run wild on rough, rocky ground. Made with recycled, vegan*, high-performance materials.
We're on a mission to create a fully circular shoe – a new Vivo made from an old one, which can in turn be made into another. The Primus 3.5 is a big step forward on this journey.

With an already mechanically recyclable outsole, the challenge is making an upper from 100% polyester, which can be recycled. The new Primus Trail 3.5 upper takes us from 34% to 76% polyester, of which 93% is recycled. Why not 100%? Because some parts of the upper still need extra durability that polyester can't yet provide. We’re working with our partners to figure out this final piece of the puzzle.

Vivobarefoot Men’s Size Chart

Ensure your Vivobarefoot shoes fit just right. Our guide includes accurate size conversions (cm, EU, UK, US), the “rule of thumb” for toe-splay, and easy 365-day returns.

Men’s Footwear Size Guide

The Rule of Thumb

Vivobarefoot deliberately fits larger—your toes need room to splay naturally. If you can fit your thumb between your longest toe and the shoe’s front, you're likely wearing the right size. Over time, as toes spread, you may need to move up a size.

How to Measure Your Feet

• Stand on a hard surface with your heel against a wall.
• Mark the tip of your longest toe and measure to the wall in cm.
• Use the measurement above to choose the corresponding EU/UK/US size.
• Measure both feet and use the longer measurement.

Sizing Tips & Returns

• Vivobarefoot shoes run larger than traditional footwear—don’t worry, this supports natural toe splay.
• If you’re between sizes, we recommend sizing up for comfort rather than over-tight fit.
• Changed your mind? Return unused shoes within 365 days for a full refund or store credit—no questions asked.