A wetsuit that doesn’t fit right will ruin your time on the water. Too loose and it flushes cold water with every wave; too tight and you can barely paddle. If you’re searching for an O’Neill wetsuits size chart, you’re already one step closer to getting the right fit, but the numbers on the tag only tell part of the story. Height, weight, and chest measurements all play a role, and O’Neill sizes don’t always match what you’d expect from other brands.
At Original Crab Island, we help visitors make the most of Destin’s waters every single day, from jet ski rentals to pontoon cruises around Crab Island. We see firsthand how the right gear changes the experience, whether you’re snorkeling a sandbar or riding out on a cooler morning. That’s exactly why we put this guide together: so you can spend less time second-guessing sizes and more time enjoying the Gulf.
Below, you’ll find complete O’Neill size charts for men, women, and children, along with step-by-step measuring instructions and tips on what to do when you fall between two sizes. Let’s get you fitted.
How O’Neill wetsuit sizing works
O’Neill builds their wetsuits to fit your body differently from how a t-shirt or pair of board shorts would. Wetsuit sizing prioritizes your height and chest measurement over your typical clothing size, which means the size on your shirt or swim trunks is almost never the right place to start. If you’ve grabbed a wetsuit based on your usual medium and found it too loose in the chest or too short in the legs, that’s exactly why O’Neill provides a dedicated sizing system built around actual body dimensions.
Your clothing size and your wetsuit size are two different things. Always use a measuring tape, not a guess.
What the size codes mean
When you look at an O’Neill wetsuits size chart, you’ll notice codes like MS, M, MT, LS, L, LT, XL, and XXL for men, and similar letter-based codes for women and kids. The letters break down simply: “S” stands for short, “T” stands for tall, and the base letter indicates body volume. So an “MT” fits someone with a medium build but a taller frame, while an “MS” fits someone with a medium build and a shorter torso.
Here’s a quick breakdown of what each suffix signals:
- No suffix (e.g., M, L): Standard height range for that build
- S suffix (e.g., MS, LS): Shorter torso and leg length within the same chest and weight range
- T suffix (e.g., MT, LT): Taller torso and leg length within the same chest and weight range
Knowing this system before you consult any size chart saves a lot of confusion. A person who is 6’2″ and weighs 185 lbs will almost always need a “T” size even if their chest measurement places them in a standard large range.
Why body proportions matter more than weight alone
Weight is only one piece of the puzzle when fitting a wetsuit correctly. O’Neill uses a combination of height and chest circumference to determine fit, and those two measurements carry more influence in the final decision than the number on a scale.
For example, two people who both weigh 175 lbs can wear entirely different O’Neill sizes if one stands 5’8″ and the other stands 6’1″. The taller person needs more neoprene length through the torso and legs, which shifts them into a tall size even if their chest measurement is identical. You can’t rely on a single number to find your fit, which is exactly why the charts break down across multiple dimensions.
How wetsuit thickness plays into sizing
O’Neill wetsuits come in different neoprene thicknesses, typically listed as a combination like 3/2, 4/3, or 5/4/3 (measured in millimeters). Thicker neoprene compresses slightly differently against your body and generally runs more restrictive through the shoulders and chest than a thinner summer suit.
If you’re choosing a 5/4 winter suit versus a 2mm summer suit, your size may stay the same, but always confirm that the chest measurement sits snug without restricting arm movement. A practical test: if you can’t lift both arms fully above your head while wearing the suit, size up.
How to measure for an O’Neill wetsuit
Before you open any o’Neill wetsuits size chart, you need three accurate body measurements: height, chest circumference, and weight. Skipping this step and eyeballing your size is the most common reason people end up with a suit that either flushes water or cuts off circulation at the shoulders. Grab a soft measuring tape and take these readings while wearing minimal clothing.
What you need before you start
You only need two items: a flexible fabric measuring tape and someone to help you measure your chest accurately. A rigid ruler or a metal tape measure won’t curve around your body correctly, so avoid those. If you don’t have a fabric tape, a piece of string and a ruler work as a backup.
The three measurements that matter
Each measurement serves a specific purpose in the sizing process. Follow these steps exactly to get accurate numbers:
Height:
Stand flat against a wall in bare feet. Place a book flat on top of your head and mark the wall. Measure from the floor to the mark in inches or centimeters.
Chest:
Wrap the tape measure around the widest part of your chest, just under your armpits and across your shoulder blades. Keep the tape parallel to the floor and pull it snug without compressing your skin. Exhale normally before reading the number.
Weight:
Use a standard scale in pounds or kilograms. Weigh yourself in the morning before eating for the most consistent reading.
When your chest and height point to different sizes on the chart, always prioritize chest fit. A suit that’s tight in the chest will restrict your paddling and breathing within minutes.
Once you have all three numbers written down, you’re ready to cross-reference them against the size charts below. If a measurement falls directly on a border between two sizes, note both sizes so you can consider suit type and thickness before making a final call.
Men’s O’Neill wetsuit size chart
The men’s sizing range in O’Neill’s lineup runs from XS through XXXL, with short and tall variants built into the middle sizes. Before you cross-reference the o’Neill wetsuits size chart below, have your three measurements ready: height in inches, chest in inches, and weight in pounds. Match all three columns, and if any one measurement points you toward a different size, defer to chest fit first.
Standard men’s size chart
Use the table below to find your starting size. The “S” and “T” variants within each size account for shorter or taller frames at the same body volume, so read across all three columns before you land on a size.
| Size | Height | Weight (lbs) | Chest (in) |
|---|---|---|---|
| XS | 5’4″ – 5’6″ | 120 – 140 | 33 – 34 |
| S | 5’6″ – 5’8″ | 130 – 150 | 35 – 36 |
| MS | 5’6″ – 5’8″ | 150 – 170 | 37 – 38 |
| M | 5’8″ – 5’10” | 155 – 175 | 37 – 38 |
| MT | 5’10” – 6’0″ | 165 – 185 | 37 – 38 |
| LS | 5’8″ – 5’10” | 175 – 195 | 39 – 40 |
| L | 5’10” – 6’0″ | 180 – 200 | 39 – 40 |
| LT | 6’0″ – 6’2″ | 190 – 210 | 39 – 40 |
| XL | 6’0″ – 6’2″ | 195 – 215 | 41 – 42 |
| XXL | 6’2″ – 6’4″ | 210 – 230 | 43 – 44 |
| XXXL | 6’2″ – 6’4″ | 230 – 250 | 45 – 46 |
What to do when your measurements don’t align
Sometimes your height and chest measurements point in opposite directions on the chart. A common example: you stand 6’1″ but carry a 38″ chest, which puts you in MT territory for height but M for chest. In this case, start with MT and check that the suit sits flush across your shoulders without pulling under the arms.
If the suit pulls at the shoulders when you reach forward, that’s the single clearest sign you need to size up, regardless of what the chest number says.
Torso length is the detail most people overlook. If the crotch seam sits more than an inch below your natural line, the suit is too long in the trunk and will allow water to flush in during active movement.
Women’s O’Neill wetsuit size chart
Women’s O’Neill wetsuits follow a parallel logic to the men’s range, but the cuts are built around a narrower shoulder, higher waist, and fuller hip ratio. This means you cannot simply convert your men’s size or assume a standard women’s clothing size will translate. When you reference the o’Neill wetsuits size chart below, use your height, chest measurement, and weight together to find where all three columns agree.
Standard women’s size chart
O’Neill designs women’s sizes with torso length and chest circumference as the primary fit drivers. If you measured correctly in the previous section, you’re ready to cross-reference all three columns below. The “S” and “T” variants follow the same short and tall logic as the men’s range.
| Size | Height | Weight (lbs) | Chest (in) |
|---|---|---|---|
| 2 / XS | 5’0″ – 5’2″ | 95 – 115 | 30 – 31 |
| 4 / S | 5’2″ – 5’4″ | 110 – 130 | 32 – 33 |
| 6 / MS | 5’2″ – 5’4″ | 125 – 145 | 34 – 35 |
| 8 / M | 5’4″ – 5’6″ | 135 – 155 | 35 – 36 |
| 10 / MT | 5’6″ – 5’8″ | 145 – 165 | 35 – 36 |
| 12 / L | 5’6″ – 5’8″ | 155 – 175 | 37 – 38 |
| 14 / LT | 5’8″ – 5’10” | 165 – 185 | 37 – 38 |
| 16 / XL | 5’8″ – 5’10” | 180 – 200 | 39 – 40 |
| 18 / XXL | 5’10” – 6’0″ | 195 – 215 | 41 – 42 |
When your measurements split across sizes
This happens frequently for women because hip and chest proportions don’t always scale together. If your chest measurement points to one size but your height points to another, fit the chest first and then check that the suit doesn’t pull at the lower back when you bend forward.
A suit that gaps at the lower back will flush water on every duck dive or wave entry, no matter how snug the chest feels.
Pay particular attention to zipper placement and neck entry style, since a suit that’s too short through the torso will pull the back zipper down and create a flush point right at your spine during active movement. If that happens, move up to the tall variant in your size.
Kids’ O’Neill wetsuit size chart
Children’s sizing follows a simpler structure than the adult range, but it still requires accurate measurements. O’Neill builds kids’ wetsuits around height and weight as the two primary fit drivers, since children’s chest proportions vary less dramatically than adults. Measure your child’s height in bare feet and their weight on a standard scale before consulting the o’Neill wetsuits size chart below.
Standard kids’ size chart
Kids’ O’Neill sizes run from 2 through 14, which correspond to age-adjacent fit ranges but are not strict age guarantees. A taller or heavier child at age 8 may fit a size 12 without any issue. Always let the height and weight columns make the final call rather than the number printed on the tag.
| Size | Height | Weight (lbs) |
|---|---|---|
| 2 | 2’10” – 3’2″ | 25 – 30 |
| 4 | 3’2″ – 3’7″ | 30 – 40 |
| 6 | 3’7″ – 4’0″ | 40 – 55 |
| 8 | 4’0″ – 4’4″ | 55 – 70 |
| 10 | 4’4″ – 4’8″ | 70 – 85 |
| 12 | 4’8″ – 5’0″ | 85 – 100 |
| 14 | 5’0″ – 5’4″ | 100 – 120 |
If your child falls at the top of a size range in both columns, size up. A suit that’s slightly generous on a child causes far fewer problems than one they’ve outgrown.
What to check before finalizing your child’s size
Neck and wrist seals are the two spots where kids’ wetsuits fail most often. If the neck opening gaps more than a finger-width on either side, the suit is too large and will flush cold water on every splash. Check that the wrist cuffs sit flush without cutting into the skin when your child makes a fist and extends their arm forward.
Bend is the other test worth doing before you buy. Have your child crouch into a squat and stand back up. The suit should move with them without pulling the back zipper or bunching behind the knees. If either happens, the suit is too short through the torso or leg, and you need the next size up.
One last fit check before you buy
You now have every number you need from the o’Neill wetsuits size chart to pick the right suit. Before you finalize your order, run one last check: confirm that your chest measurement is the deciding factor when height and weight point in different directions. If you’re between sizes, size up and test shoulder movement. A suit that pulls when you raise both arms overhead is too small. A suit that gaps at the lower back is too short through the torso.
Both issues flush water during active movement, and neither one fixes itself once you’re in the ocean. Getting the fit right from the start means your time on the water stays focused on the experience rather than your gear. If you’re heading to Destin, Florida, the Gulf has plenty to offer a well-fitted snorkeler or first-time surfer. Check out everything Original Crab Island has waiting for you when you’re ready to get out there.
