Search

Search

309600-01-M41

Vivobarefoot Primus Trail 3.5 FG Mens Barefoot Shoes

Size Guide
Size Guide - Vivobarefoot

Place a piece of paper larger than your foot against the wall. Ensure that the wall is flat, and if there is any skirting, it is also flat. 

Stand on the paper with your heel against the wall. Ensure that the floor is hard and that the paper does not slide under any gap between the floor and the wall/skirting.

Mark the paper where your longest toe reaches with the pencil. Remember to not tuck the pencil under the toe as you want an accurate maximum measurement.

Measure the distance from the end of the paper to the toe line with a ruler or tape measure.

Repeat with your other foot, they might be different – trust us on this one! – and then use the longest measurement.

Use our conversion tables below to work out your recommended fit.

WOMENS FOOTWEAR SIZE GUIDE

FOOT LENGTH (CM) EU UK US
21.2 - 22.1 35 2.5 4.5
22.2 - 22.8 36 3 5
22.9 - 23.5 37 4 6
23.6 - 24.1 38 5 7
24.2 - 24.8 39 6 8
24.9 - 25.4  40 7 9
25.5 - 26.1 41 8 10
26.2 - 26.8 42 8.5 10.5
26.9 - 27.4 43 9 11

MENS FOOTWEAR SIZE GUIDE

FOOT LENGTH (CM) EU UK US
24.6 - 25.5 40 6 7
25.6 - 26.2 41 7 8
26.3 - 26.9 42 8 9
27.0 - 27.5 43 9 10
27.6 - 28.2 44 10 11
28.3 - 28.9 45 11 12
29.0 - 29.6 46 11.5 12.5
29.7 - 30.3 47 12 13
30.4 - 30.9 48 13 14
31.0 - 31.6 49 14 15
31.7 - 32.3 50 15 16
32.4 - 33.0 51 16 17

TODDLERS FOOTWEAR SIZE GUIDE

FOOT LENGTH (CM) EU UK US
9.4 - 10.2 18 2 3
10.3 - 10.9 19 3 4
11.0 - 11.6 20 4 5
11.7 - 12.3 21 4.5 5.5
12.4 - 13.0 22 5 6
13.1 - 13.6 23 6 7
13.7 - 14.3 24 7 8

PRESCHOOL FOOTWEAR SIZE GUIDE

FOOT LENGTH (CM) EU UK US
14.4 - 14.9 25 8 9
15.0 - 15.6 26 8.5 9.5
15.7 - 16.3 27 9 10
16.4 - 17.0 28 10 11
17.1 - 17.6 29 11 11.5

KIDS FOOTWEAR SIZE GUIDE

FOOT LENGTH (CM) EU UK US
17.7 - 18.3 30 11.5 12
18.4 - 19.0 31 12 13
19.1 - 19.6 32 13 1
19.7 - 20.2 33 1 2
20.3 - 20.9 34 2 3

JUNIOR FOOTWEAR SIZE GUIDE

FOOT LENGTH (CM) EU UK US
21.0 - 21.7 35 3 4
21.8 - 22.4 36 3.5 4.5
22.5 - 23.1 37 4.5 5.5
23.2 - 23.8 38 5 6
23.9 - 24.4 39 6 7

RECOMMENDED

SNUG

 

This shows how a shoe would fit snug. It’s still a correct fit, but with less space around and at the front of the toebox. 

RECOMMENDED

 

This is the shape of the recommended fit of Vivos. Remember, it might not be your preferred fit.

SPACIOUS

 

If you prefer a roomier fit or think you have wider-than-average feet, you might consider going a size up.

Colour: Mineral
Mineral
Obsidian
Insignia Blue/Gum
Size: US 8 EU 41

1 item left

2026-02-10 2026-02-17 Ready Stock 現貨訂單 Pre-order 預售訂單 Gift Cards 禮品卡 Error 錯誤

Hit the trail to rewild yourself and reconnect with nature. The Primus Trail 3.5 FG is a light, durable, flexible trail-running trainer that brings us one step closer to circular footwear.

Firm Ground outsole

Stand firm on multiple terrains.

ORTHOLITE INSOLE

The Ortholite Performance Insole is made of 98% recycled polyurethane foam, which helps reduce waste and the use of virgin plastics.

BREATHABLE MESH

Breathable, lightweight and comfortable.

WEIGHT

Based on a single shoe in Men's size: EU 42 | UK 8 | US 9

281g

MATERIALS

UPPER

Vamp: 100% Recycled polyester mesh, Overlay: 95% recycled polyester/5% recycled spandex

LINING

Mesh:100% Recycled polyester, Microfiber: 80% recycled polyester / 20% Polyurethane

FASTENING

Laces

LACES

100% Recycled polyester

INSOLE

Ortholite Performance: 98% Recycled Polyurethane Foam / 2% Water-based binding agent

OUTSOLE

90% Synthetic rubber / 10% Natural rubber

MADE IN VIETNAM

CARE

Cleaning

Brush off mud and clean with a damp cloth

Drying

Remove insole and dry at room tempreture. Keep out of direct sunlight and avoid putting on a radiator.

Aftercare

LIQUIPROOF PREMIUM PROTECTOR. With wear, your shoes may loose some water resistent quality that is applied to the textile of the shoes. This product can be used to replenish the water repellent qualities.

Repair Options

Laces and insoles can be replaced.

End of life

Once you can’t repair or don't need them anymore, send us your old Vivos and we’ll make they sure they’re given a second life, or if they’re really well-loved, we'll store them until we launch our recycling solution.

Feel the earth

Tough, all-terrain trail trainers  one step closer to circularity

Why go barefoot

Wearing Vivos for 6 months increases foot strength by 60%

Fit

Better Balance and Posture

Foot-shaped fit enables toes to splay supporting balance and a stable base of support.

Feel

Improved Coordination And Agility

Thin sole allows the thousands of nerve endings in each foot enabling the sensory feedback the brain needs to move with skill.

Flex

Improved Strength and Natural Movement

Flexible footwear let the muscles and tendons load and recoil, supporting stronger, more resilient feet over time.

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.

multi-terrain

Giving you grip and ground feel on everything from wet and dry, rocky and firm terrain.

Urban

Stripped-back soles for barefoot living — so you're never too far from nature, even in the city.

Fit, Feel, Flex

For natural stability, natural sensory feedback and natural strength.

Firm Ground outsole

The Firm Ground outsole is made sticky rubber compound that provides excellent grip and durability. With a 3mm base and 2.5mm lug height, plus a textured arch for zonal grip (ideal for technical trail movement), this sole will keep your feet firmly planted on multiple terrains - wet to dry, concrete to rocky.

Sole base

3mm

Tread Depth

2.5mm


Welcome back the wild.

Human beings aren’t separate to nature, we are nature. When we listen to its rhythm and connect to its intelligence, we thrive. It's time to get outside and rewild.