They look oversized, unusual and almost too bulky to belong anywhere near a football pitch.
But some players at the 2026 World Cup have been using these strange-looking covers over their football boots, and they are not fashion accessories.
So what are they, why are players wearing them, and could they actually make a difference in the heat?
They Are Not Football Boots
The oversized footwear is part of the new adidas CLIMACOOL SYSTEM, created to help players cope with the hot and humid conditions expected during the 2026 World Cup.
The system contains three separate pieces:
- A cooling vest
- An insulating jacket
- A cooling overshoe
The strange-looking overshoe is worn over the player’s normal football boot. It is not used during the match itself and does not replace the player’s actual boots.
How Does the Cooling Overshoe Work?
The overshoe contains a cooling gel that transfers cold directly around the foot and boot.
According to adidas, it can reduce foot temperature by around 2°C within seven minutes. The aim is to combat overheating and swelling while preserving the sensitivity and dexterity players need for passing, dribbling and shooting.
That last point matters. Cooling the feet too aggressively could theoretically leave them feeling numb or less responsive, so the system is designed to provide cooling without compromising how the player feels the ball.
Why Is This Needed at the 2026 World Cup?
Several host cities are expected to experience temperatures above 30°C, with humidity adding another layer of difficulty.
Footballers already generate a large amount of internal heat while sprinting, pressing and repeatedly changing direction. In hot conditions, managing body temperature can become an important part of preparation and recovery.
The cooling overshoe therefore targets one specific problem: hot, swollen feet inside tight performance boots.
The Technology Started in Formula 1
The CLIMACOOL SYSTEM was not originally created for football.
Its development began with technology designed to help Mercedes-AMG Petronas Formula 1 drivers cope with extreme cockpit temperatures. Adidas later adapted the concept for football through testing with clubs including Manchester United, Juventus and Arsenal.
The football version was refined using feedback from players and medical staff, including practical details such as making the vest easier to put on and remove.
What Do the Vest and Jacket Do?
The overshoe is only one part of the complete system.
The cooling vest contains a specialised gel that is frozen before use. As it slowly thaws, it cools the torso, abdomen and back.
An insulating jacket is then worn over the vest to trap cold air and prolong the cooling effect. Adidas says the vest-and-jacket combination can reduce core body temperature by as much as 0.5°C and skin temperature by up to 13°C.
Will Players Wear the Overshoes During Matches?
No. The overshoes are designed for preparation, cooling breaks, the substitutes’ bench or recovery periods, not for running, tackling or striking the ball.
The player keeps the normal football boot underneath, removes the cooling cover and can then return to the pitch without changing footwear.
That makes the system faster and more practical than taking the boots off completely.
Can You Buy Them?
Not at the moment.
Adidas has confirmed that the complete CLIMACOOL SYSTEM will be supplied to its partner federations at the World Cup. It has not announced a general consumer release for the cooling overshoe.
Even if a retail version appears later, this is specialist performance equipment rather than a replacement for choosing football boots that fit correctly.
For normal players, the basics still matter most: correct sizing, appropriate foot width and the right soleplate for the surface.
Our football boot buying guide explains the key factors to check before choosing a pair.
If your boots often feel too tight or too loose, our football boot width chart can help determine whether your feet are narrow, standard or wide.
A Gimmick or a Genuine Performance Tool?
The appearance makes the overshoe easy to dismiss as a social-media gimmick. It is huge, bright and looks unlike anything normally seen beside a football pitch.
But the idea behind it is practical. Elite sport increasingly focuses not only on equipment used during competition, but also on preparation, temperature management and recovery.
Whether a two-degree reduction in foot temperature produces a measurable match advantage will depend on the player and the conditions. However, in extreme heat, even small improvements in comfort and heat management may be valuable.
