How to Fit Your Hydration Vest

Gina Lucrezi


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A few weeks ago I received an Ask The Trail Sisters submission regarding: how do I correctly fit my hydration vest?

This is a very good question, but one that is hard to answer. As I began to construct a response back, it occurred to me that I should create an informative and educational resource for everyone and anyone looking for help on successfully fitting their hydration vest.

First thing’s first. Not all brands fit alike, and to make things even more complicated, vests may fit differently depending on how much (or how little) weight is added to the them, and where!

To produce a helpful guide on “how to fit your hydration vest”  I reached out to the leading hydration brands for their input, and instruction. After all, who can explain “fit” better than they can!



Our women’s specific vests fit similar to the unisex ones, however there are a few key differences to point out. They’re cut shorter in the front and sides, plus they’re narrower in the shoulders. The end result is a snug, apparel-like fit, designed specifically to fit the female form.

Start by measuring both the circumference of your bust, and your sternum under your bust, then check the size chart tag to see which size you should start with.

Fitting instructions are the same as the unisex vests.

  • Loosen all straps before putting on the vest
  • Once on, buckle the straps and adjust up and down on the slide rails
  • Now tighten them so the vest fits snugly, but you can still breathe comfortably

The vest should fit securely around your shoulders, chest, lower back, and below your armpits.

Test it out on a short run. The vest shouldn’t bounce, shift, or swing. It should hug your body like a second layer of technical apparel.

Stephanie Violett fitting her VaporHowe vest.

My favorite highlight of the VaporHowe is how well the vest fits many female body types. It’s designed to fit a woman’s body, especially with the ability to move the straps up and down, and tighten the pack down so it doesn’t bounce, rub, or chafe. Females are not smaller males, and a pack should not be made to reflect that. I love that NATHAN started from scratch to create a product that was ideal for running hours without issue. Everything from the material, to the straps, to the bladder is designed to fit and be comfortable as well as functional. The Vapor series is the first product with many sizes available – from XXS-XL. 6 sizes to choose from. This is CRUCIAL because each person is different. No two women are alike, and that’s what makes it beautiful. – Stephanie Violett

Check out more NATHAN vests

NATHAN information provided by: Maggie Guterl – Marketing Coordinator


Ultimate Direction 

For the Ultimate Direction 3.0 Signature Series Vests and Vestas we have three adjustability components to our harness system: Two sternum straps up front and lateral tightening straps on either side. These components allow UD to fit a large range of bodies because of the versatility and ease of use. Please see the “how to” below:

1. – Define your size by measuring at the bottom of your ribs: Small (23in-32in), Medium (30in-39in), Large (37in-46in) in Unisex or S/M (23in-32in), M/L (30in-40in) in Women’s Specific. Put on your Vest or Vesta of choice.

2. – Tighten or loosen the sternum adjustment straps horizontally and move them vertically to place the shoulder straps where they are most comfortable on your chest.

3. – Tighten the “lat” straps to ensure a snug and secure fit while keeping everything in place.

Ultimate Direction Fit Guide

Check out more Ultimate Direction vests

Ultimate Direction information provided: Anders Mavis – Designer & Developer


Camelbak Products


When purchasing a hydration vest, the number one thing we hear complaints on is improper fit. There is nothing worse than feeling the discomfort of an extra layer; that in reality should have that barely there feel.  Today Hydration vests are more than ever just like a sized piece of apparel, but with the added benefit of aiding in proper hydration and fueling so you can perform your best. 

 1. – First step in how to properly fit is understanding size: At Camelbak, all of our vests are unisex, but there are options that are  “one size fits all”  OR  options that are sized like apparel. Both have adjustment points to get you a more precise fit. (In the future we will be looking to expand into women’s sizing with specific features to fit a women’s frame. This is something we are super excited about as a brand and run category focus).

2. – Once you know how the product you are purchasing is sized, the next step is to have a general idea of your own measurements. Our fit specialist at CamelBak suggests measuring two critical spots  – Chest circumference and Natural waist circumference. Often times these measurements will help guide you to the best size range and fit that all brands typically list on their products. A quick search on google will give you the proper how-to for measuring. Most run shops will also be more than happy to assist in this step. 

3. – Now comes the fun part! Trying on the product. My number one recommendation here is to understand where your points of adjustment are. With vests that have side adjustments like our Ultra 10 and Circuit vests, you can get a more dialed fit by cinching down the vest at the sides. This also helps with varying cargo loads and water; you can adjust on the go.  All of our vests also have dual sternum strap adjustments that can be moved laterally up and down. Pro Tip: Move these around and don’t expect that the off -the-shelf placement will be best for you. All body shapes are different and the location of these straps make a huge impact on ensuring a snug fit and minimal movement. If available, use a mirror so you can see where you are positioning these.  Once set, you likely do not have to move them around again

4. – The next important part to proper fit is trying on the vest with your filled hydration and cargo inside. This will not only change the way the product feels on, but you get a more realistic expectation of the weight and placement on where your items will be. On our Ultra Pro Vest and Nano Vest, these come with up front access Quick Stow Flasks. Fill these up and get a sense of how they slide into the pockets and feel against your body. An empty vest is not going to fit the same way a packed out one will feel. 

5. – Last, take a test run or even do a quick jog in the vest.  This always feels a bit silly if you are in the store or at home, but at least you will get an idea of any immediate concerns.  In a store, try on the next size up or down. Ensuring you find a vest that is not too large or too small is critical to making the gear something you do not have to think about on your run. There is nothing worse than a vest that moves around, too tight or causes chafing.

Camelbak Female Athlete’s on “Packing Out” with Camelbak:

Meredith Edwards – @merejune


“For most of my ultra’s I run in the Ultra Pro Vest. With my focus manly being UTMB this pack is perfect because it fits all the required gear needed for the race.  Because there is so much required equipment I go up a size to a Medium. Anything else I am a small, but with a pack full of gear I need it to all fit and still be comfortable. The Medium allows the back to expand and hold everything. With 1 liter of water in the front it really balances everything out and feels comfortable when running especially downhill. I find the water pockets to fit really low on my chest not causing any issues with my ladies when running.  If I am running any other race that just requires me to run with food and water I go down to small. If a pack is too big you can tell when you’re running and the back moves around a lot and can be quite annoying. It also causes me to rub around my rib cage which can be painful. I look for a snug fit, but not to snug where I fill my chest (expand) and breathe.”

Jax Mariash – @jaxmariash


“Many folks often wonder how to pack your essentials for a long run ahead. All of the pockets on the Ultra Pro vest make it easy to get to your snacks, extra clothing and there is a perfect pocket for your iPod to keep you bumping for many miles. I love to have storage and accessibility and the Ultra Pro offers both. Here is a sample of where I slip in my favorite treats, clothes and flasks to go miles upon miles. 

For fit, I love my packs to be super snug on me. When running long miles, you do not want your pack to be shifting around on your body. The great thing is that the Camelbak vest has the option to move the two front clips around to make sure the vest fits snug on your chest. As I eat off my supplies for a long run, it is easy to tighten the straps on my chest to keep the vest snug. The ultra-light vest has a cut that fits snug, but does not chafe. It is super light and the flask pockets are easy to slip your flasks in and out of and to tighten down as your drink your fluids.”

Visit Camelbak

Camelbak information provided by: Julianne Ryan – Product Manager



How to fit a Salomon Hydration Vest

1. – Think about your training goals. 

How long are your longest training runs and races?  How much gear do you take with you (jacket, trekking poles, headlamp, snacks, gloves, phone, sunglasses, sunscreen, water, etc.)?  This is important when selecting a pack because you will want to have sufficient capacity to carry your standard gear during the length of your run.

2. – Reference Brand’s size chart (below)

Have a friend measure your torso diameter (just below your bust, top of your rib cage.  Also refer to size chart photo below).  If you are between sizes, purchase the smaller size.

Our packs use such lightweight elastic and 4-way stretch material, you want to be sure after it’s loaded up with water and gear you still have room to adjust/tighten the sternum straps.

Salomon Fit Guide


3. – Try the pack on empty with what you would typically wear while running.

4. – Pull the tab across your chest and attach sternum straps (twin links). 

You do not want the right and left sides of the vest to touch in the center of your chest.  The sternum straps are adjustable.  Adjust to what’s comfortable for you.  Most of our female athletes prefer the top sternum strap at or just above the bust and the lower strap in line with the lower rib cage.  With the empty pack on, there should be no rubbing or shifting.

5. – Stuff your pack with gear that you would commonly use on the trail. 

6. – Again, adjust the straps to a comfortable position and then move around.

I recommend doing things that runners need to be able to do without feeling restricted or irritated by their pack. Make sure you can breathe comfortably, swing your arms, and jump around with no issue.  Our hydration systems should fit like a vest and not a backpack. The weight will be distributed throughout your body and not just on your shoulders.

7. – Put on your favorite Salomon running shoes and have fun!!

Anytime you buy gear online, we suggest you leave the tags on until you are satisfied with the fit.

Keep in mind our Skin and Sense Packs are unisex.  Size charts reflect this.

Check out Salomon packs

Salomon information provided by: Katie Copeland – Apparel and Gear Manager, and Aliza Lapierre – Salomon Athlete



First:  Is the vest you own or desire to purchase, a fitted race vest, meaning sized, or is it one size fits most?

If it is fitted:  There are two measurements that are changed when going from a one size to the next in a race vest.  Both the torso length and girth or dimensions around the chest and torso.  The larger the vest, the longer the torso and the larger the girth.  The best way to know for sure is to try the vest on with similar clothing that you will be wearing.  Please note that more clothing will take space in the vest.  Also a pack that is fully loaded will fit a little different that an empty pack. 

So here are my suggestions:

1. – Put on the clothes that you will be primarily wearing under the race vest.

2. – Load the pack with the contents or similar capacity that you will be carrying.

3. – Put the vest on and see where the pockets fall across your chest and how much space you have in between the pockets. This is personal preference.  Some runners like the pockets very close together.  Others like them very far apart. 

4. – Attach the Cords on the Max O2 sternum and tighten enough to keep the pack from moving but not so much that it restricts your breathing. Most runners try to wear their packs too tight. 

For a One Size fits most:

1.  Put on the clothes that you will be primarily wearing under the race vest.

2. – Load the pack with the contents or similar capacity that you will be carrying.

3. – Loosen the side straps and Max O2 Sternum.

4. – Put the pack on and position the front pockets where you would like them to be. Close together or far apart. 

5. – Attach the cords on the hook for the Max O2 sternum and adjust the Max O2.

6. – Then tighten the side straps to snug the pack down for comfort and stability.

Practice accessing the pockets that are available while wearing the vest and imagine what it will be like after many hours of running in a fatigued state.   This will be one thing that will help you determine if the vest fits properly.

Check out UltrAspire packs

UltrAspire information provided by: Bryce Thatcher – President


Orange Mud

Finding a pack that fits ladies curves can be a bit tricky. That’s why we designed the Endurance Pack for ladies first, ensuring maximum adjustability in the front and sides. When first putting on the pack, cinch the sides up decently snug, this sets the side fit. Then adjust the front chest straps as you see fit. They do not have to be tight at all, something common across all of our packs, as we want you to be able to breathe while running and feel no restriction.

The chest harness is where it’s all at, so the first step is to dive into this area. Out of the package the pack has two adjustment straps, one high on your chest and one lower. These have a unique clip with various segments in the front chest harness that can be moved up and down to find the optimum placement. If you’re a petite runner, there is a good chance that it will fit great straight out of the box which is by having the top segment in the #1 segment, and bottom strap in the #3 segment. If you’re more curvy up front, you’ll likely move the bottom strap down to the #4 segment area which will yield an optimum fit. For those with DD and larger chest, it may help to move the bottom strap to the #2 segment or you could get rid of it all together. Our fit video below explains how to adjust this as well. Keep in mind we’re always here to help too, just shoot us an email or call us from our contact page and we’ll get right back to you!


The frame of the pack uses a material that doesn’t give. This is very important to stabilize your fluids and gear whether the pack is full, all the way to empty. The only elastic that we use is on the pockets and rear cargo which compresses the load from full to empty. On top of a great fit for you, your gear will ride super stable too, whether it be 2 miles or 200 miles!

Chest and shoulder pockets

These are one of the most awesome parts of the pack. Some prefer to use 600ml soft flasks in these, some use them for backup gear and nutrition. That is totally up to you. We don’t suggest bottles up front as hard bottles aren’t too friendly for ladies curves, not to mention that they slosh a lot. Our general focus is arm warmers, sunglasses, nutrition, and sunglasses in these pockets. The top shoulder pockets are used for things like electrolyte, chapstick, sunblock, and generally we put them in a ziplock bag for this area.

The hose tube is likely longer than you prefer. We suggest wearing the pack a few times, then cutting it 4” below the elastic in front of the shoulder pockets. This video shows this quite well.

Visit Orange Mud

Orange Mud information provided by: Josh Sprague – Founder


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Gina Lucrezi

Gina Lucrezi

Gina has always been stubborn and bold, so when it came to advocating for women’s rights and equality in the outdoors, she was bound to make some changes. As the founder of Trail Sisters, Gina’s goal is to help create opportunities and grow participation in women’s trail running. Gina is also a professional ultra trail runner, and when she’s not on the trails logging miles, she’s most likely trying to potty train her new Airedale pup, Ezra.

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5 thoughts on “How to Fit Your Hydration Vest”

  1. This is fantastic. Super helpful for buying and theoretically fitting for sure. Would love to see how some real busty gals wear their packs. All these pictures are elite lean women. I need a visual of some DD+s with loaded pockets. Strap height I can figure it but tightness of the side vs. front. How much should it “close”? Is one. Rand better? That being said, this is great info.

  2. Amelia, I too have M/L breasts. I’ve tried so many packs but alas the Salomon Advance Skin Set is the only pack I’ve been able to find that fits properly. Nathan’s Vapor line gets smaller with each new model. The VaporAiress S/M used to fit ‘ok’ with some bouncing but now I can barely squeeze into the new black/Cockatoo L/XL I recently purchased. I tried the XL in the Vaporhowe but it was so constricting – really small. I would love to hear how the Vaporkrar fits a woman.

  3. Helpful stuff!
    I’ve run through my share of hydration vests over the years. Right now, it’s all about storage space for me and fit comes second. Love how many brands are no catering to women though! Rock on!

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