Downhill ski boots

Ski boots are the key link between your body and your skis, so finding boots well-matched to the size and shape of your feet is a high priority.

This article helps narrow your search for the best ski boots by focusing on fit and performance—style and color are secondary considerations.

Shop REI's selection of downhill ski boots.

Know Your Skier Profile

While skis are categorized by terrain and end use (such as all mountain, freeride and so on), ski boots are best shopped by your ability level. Be honest in your self-evaluation.

  • Novice: These boots are typically soft flexing, comfortable and warm. They're best if you're new to the sport or you've been at it for a while but enjoy skiing leisurely on groomed green and blue runs. A soft flex does make it a bit harder to control the ski; go a step up if you expect to progress quickly.
  • Intermediate: These boots deliver increased responsiveness to improved turn-carving skills and higher speeds. They're ideal for those who can comfortably ski blues and easier black runs and are ready to tackle steeper terrain, moguls and ungroomed snow.
  • Advanced: These are the stiffest, most responsive boots you can buy. They're designed for those who ski with confidence, speed and aggressiveness on the steepest and most challenging terrain. Some offer features such as shock absorption for landing air or slamming bumps.

Not sure? Think about the other sports or activities you enjoy. How far and how quickly do you usually progress?

Ski boot

Ski Boot Styles and Features

Ski boots consist of a hard outer shell for support and soft liner for cushioning and warmth.

  • Most adult boots are "front-entry overlap" designs, meaning that they open in the front like hiking boots and are secured by 3 or 4 buckles.
  • Some kids' boots are "rear-entry" style. These models open in the back, which makes them more comfortable and user-friendly for beginners.

Outer Shell

The hard plastic outer shell varies in stiffness from boot to boot. Soft plastics flex easily and are more comfortable and forgiving. Stiff plastics are more rigid but offer greater response and precision. The more rigid your boot, the more power transfers to your ski's inside edge.

Most advanced-level boots combine multi-density materials to make boots stiff in critical areas of energy transfer, but soft in other areas. Very stiff racing boots can be uncomfortably rigid for general use.

Manufacturers rate boots on a flex index. The higher the number, the stiffer the boot. product pages list the flex index under the "specs" tab.

Unfortunately, flex index ratings are comparable only within a manufacturer's line, so the best way to compare when shopping is to put a boot on each foot, lean forward and flex them.

Tip: Boots will have a softer flex at a warm indoor temperature than they will out on the ski hill.


Most boots come with some amount of heat-moldable material in the liners. Typically, more expensive boots will feature more heat-moldable material. Some liners have down-filled toe boxes for added warmth.

There are several liner types to choose from:

  • Thermal-formable foam uses your foot’s heat to achieve a custom fit. They break in after a day or so of skiing.
  • Custom thermal-formable foam uses an artificial heat source to achieve a custom fit. Though best done at REI or other ski shops with boot-fitting expertise, it is possible to do this at home with your oven or a hot-air blower.
  • Molded foam liners are made by molding liner tongues and foot sections individually, then sewing them together for a precise fit. These are not heat-moldable.

Ski/Hike Mode

Do your ski days include hikes up sidecountry ridges to find untracked powder? Many medium- to high-end boots let you separate the upper shell from the lower boot for more comfortable walking. When you're ready to ski the descent, you can lock the upper and lower shell together to maximize power transmission.

Flex Adjustment

Some ski boots have a switch so you can adjust the boots' stiffness to match a particular type of skiing, like powder, groomers or bumps. It is usually located on the back of the boot, around ankle height.

Boot Sizing and Fitting

Downhill ski boots use mondo sizing, which refers to the boot’s inner sole length in centimeters. Sizes are not always uniform by brand or even from one model to another.

Mondo Ski Boot Sizes to US Sizes

Mondo 21.5 22 22.5 23 23.5 24 24.5 25 25.5 26
Women's US 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5
Men's US NA NA NA 5 5.5 6 6.5 7 7.5


Mondo 26.5 27 27.5 28 28.5 29 29.5 30 30.5
Women's US 10 10.5 11 11.5 12 NA NA NA NA
Men's US 8.5 9 9.5 10 10.5 11 11.5 12 13

Fitting a Boot

If at all possible, have yourself professionally fit by an REI ski boot specialist or other qualified person. This may be the most important advice in this article.

He or she will have you try on several boots to gauge what feels best to you. It’s generally best to size down from the conversion chart since linings eventually compress (“pack out”) over time. Unless you start out with snug boots, they may loosen enough to compromise control. Don't buy your boots too big!

Here are some boot try-on tips:

  • Wear thin, synthetic ski socks. No thick hiking socks, no cotton.
  • Feet tend to swell over the course of the day. Try on boots in the afternoon or evening when they are largest.
  • When standing straight up, your toes should brush the end of the boots, but they shouldn't be crammed or turned under.
  • When in a ski-tuck position, your toes should just barely pull away from brushing the front of the boot. The fit should not be painful.
  • When flexing your knees, your heels should stay down.
  • Walk around and stand in the boots for at least 20 minutes.

Fit Modifications

Most boots will likely need some modification to get the best possible fit. Also, your feet may not be the same size, so your boots may need to be adjusted to fit them. This is another reason you should always get a professional fitting.

Boots can be adjusted in various ways:

  • Add custom footbeds to fit your feet.
  • Use a heat gun to soften and mold the shell for more toe space.
  • Use a board or heel wedge to lift the heel.
  • Add foam pads under the heel.
  • Stretch or grind the liners.

Other Fit Considerations

Women's boots: Women's calves are shaped differently from men's—the calf muscles are shorter, larger and lower on the leg—and women's heels tend to be narrower. Women's boots are designed to accommodate these differences.

Custom footbeds: As noted above, these insoles are a popular way to improve fit and support. Your options:

  • For a little extra support, try a cut-to-fit footbed. REI carries these.
  • For a more customized fit, get a custom-molded cork footbed. The footbed is heated, vacuum molded and massaged to fit your foot—a 25-minute process. Many REI stores make custom-molded insoles. Contact your local store to check.
  • If you have known foot issues, choose a physician-made orthotic.

Canted cuffs: Boot cuffs should fit snugly when the buckles are latched to the middle rungs. A good calf fit means no painful pressure. Let your ski-boot specialist help you make adjustments as needed.

You may be one of the more than 75% of skiers who are knock-kneed or bowlegged. A cuff cant can help balance your stance. To check, stand with your feet aligned under your shoulders and look in a mirror. Bring your feet toward one another slowly.

  • Bowlegged: Your feet touch first.
  • Knock kneed: Your ankles touch first.

Cuff canting aligns the boot cuff with bowed or knock-kneed skiers. Any adjustments with the cuff should complement your stance, not alter it.

When to Buy New Ski Boots

Ski boot life expectancy varies. If you ski regularly and you’re hard on your boots, you may need to replace them every few seasons. Don’t wait too long; boot liners eventually tend to “pack out” which can compromise fit and performance.

Maintaining Your Ski Boots

To maximize the life of your ski boots, follow this advice:

  • Dry out your boots after use. Remove the liners and let them dry at room temperature or use a boot dryer. Do not dry the boot shells or liners near a heat source like a fire or baseboard heater.
  • Wipe down the shells if you've walked through mud or dirty slush.
  • Store your boots with the buckles and straps closed so that the hard plastic shell retains its shape.

Usage tip: On the way to the slopes, keep your boots inside the car, instead of the trunk, so they're warm when you put them on.