Women's Swim Shorts & Board Shorts: Lengths and Fit | HauteFlair

HauteFlair EditorsUpdated August 202612 min readSwimwear & Separates

Quick Answer

What is the difference between swim shorts and board shorts?

Board shorts were built for surfing and swim shorts were built for swimming, and every difference between them follows from that. A board short has a longer inseam, a flat non-elasticated waistband secured with a lace-up tie, and a tightly woven fabric with little or no stretch. That combination resists abrasion against a board, dries fast, and stays closed when a wave hits. General women's swim shorts are usually shorter, cut from stretch swim knit with 15 to 20 percent elastane, and secured with an elasticated or bonded waistband and an internal drawstring, which is more comfortable to swim and move in. Neither is better; they are answers to different problems. What decides whether either pair stays put is the same in both cases, and it is not the size. It is the leg hem. A bonded edge or an internal silicone gripper holds the hem where you put it. A plain hemmed edge travels up the thigh, and that is the single most common complaint about the category.

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Swim shorts get bought on length and colour, and abandoned because they ride up or chafe.

Both of those are decided by two details that almost no listing highlights: how the leg hem is finished, and where the inseam puts it on your thigh.

Swim vs Board Why They Ride Up Choosing a Length Waistbands What to Wear Under What to Pair With FAQ

Quick Answer: What to Check

Board shorts: woven, longer, lace-up flat waist. Built for surf and abrasion.
Swim shorts: stretch knit, shorter, elastic or bonded waist. Built for swimming and comfort.
The leg hem decides riding up. Bonded edge or silicone gripper, not a plain hem.
Pick the inseam so the hem misses the widest part of your thigh.
Bonded flat waistband with internal drawstring for a clean line and real adjustment.
Check whether they are lined. Unlined needs a swim brief, never ordinary underwear.
Flatlocked seams, because raised seams against wet skin chafe fast.

2 typeswoven board shorts and stretch swim shorts, built for different water.

The hemnot the size, is what stops them travelling up the thigh.

4-6 ininseam is the general-purpose range: enough to stop chafing, little enough to swim in.

Two Garments, Two Jobs

Board shorts came from surfing, where the garment has to survive being dragged across a waxed board, dry quickly in wind, and stay fastened when a wave hits. Swim shorts came from swimming, where the priorities are stretch, low drag and comfort against skin. Every construction difference between them traces back to that split.

	Board shorts	Swim shorts
Fabric	Tightly woven polyester, little or no elastane	Stretch knit, typically 15 to 20 percent elastane
Inseam	Longer, commonly 7 inches and up	Shorter, commonly 2 to 6 inches
Waistband	Flat, non-elasticated, lace-up tie or hook closure	Elasticated or bonded, internal drawstring
Stretch	Minimal. Movement comes from cut and side slits	Substantial. Moves with you
Best for	Surfing, paddleboarding, abrasion, sun coverage	Swimming, general beach and pool wear
Drag in water	Higher. More fabric, no stretch	Lower. Shorter and closer-fitting
Lining	Frequently unlined	Frequently lined

The practical consequence is that you can swim in board shorts perfectly well, and they will feel like more work than a stretch short over any distance. And you can wear swim shorts to surf, and they will abrade faster. Choosing between them is a question about what you are doing rather than which is better made.

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Why They Ride Up, and What Stops It

This is the reason swim shorts get worn twice and then left in a drawer, and it is almost entirely a construction problem.

Macro of a silicone gripper strip running inside the leg hem of a pair of swim shorts

A silicone gripper inside the leg hem. It holds lightly against skin so the hem has something to resist against when the thigh moves underneath it. A plain hemmed edge has nothing.

A short leg is a tube of fabric sitting on a thigh that changes circumference as you walk, sit and swim. Every step slides the fabric slightly upward, and nothing pulls it back down. Over an afternoon the hem migrates, which is both uncomfortable and the point at which thigh-on-thigh contact starts.

Two things fix it, and a third makes both work better.

What Holds the Leg Hem

Most effective · direct gripAn Internal Silicone Gripper StripA narrow band of silicone bonded inside the hem, gripping lightly against skin so the fabric cannot slide upward. It is the most reliable solution and it adds no bulk, so the hem stays flat under a cover-up. Some people find silicone against wet skin slightly tacky, which is the only real drawback. It is visible in product photographs showing the inside of the leg.

Effective · no ridgeA Bonded or Laser-Cut Leg EdgeAn edge sealed rather than folded and stitched, which lies completely flush against the thigh. It grips less actively than silicone but has more contact with skin than a rolled hem, and it removes the raised ridge that both chafes and catches. Under fitted clothing it is invisible, which matters if the shorts double as beachwear.

Structural · where the hem landsAn Inseam That Misses the Widest PointA hem finishing at the widest part of your thigh sits on a slope and slides both ways. A hem finishing above it, at the narrower upper thigh, or below it toward the knee, has somewhere stable to sit. This is why very short and genuinely long shorts often stay put better than mid-length ones, and it is worth measuring rather than guessing.

Does not work · worth namingSizing DownThe instinctive fix and the wrong one. Tighter shorts grip the thigh harder, which makes them ride up into a tighter roll rather than staying flat, and they become uncomfortable at the waist. If the hem has nothing holding it, size is not the variable to change.

Choosing a Length

Inseam is the measurement to choose first, because it determines coverage, drag and where the hem sits.

Inseam	Sits	Best for
2 to 3 inches	Upper thigh, boy-cut	Swimming with least drag. Least thigh coverage, so chafing is possible.
4 to 6 inches	Mid-thigh	The general-purpose range. Enough fabric to stop chafing, short enough to swim in.
7 to 9 inches	Lower thigh, board short length	Sun coverage and abrasion resistance. Noticeably more drag when swimming.
Knee length	At or just above the knee	Maximum coverage. Best for surf, paddleboarding and long days out of the water.

Measure your thigh before choosing an inseam

Stand up and find the widest point of your thigh, then measure from your crotch down to it. If a pair of shorts has an inseam close to that number, the hem will sit on the widest point and will slide. Pick an inseam either shorter or longer than that measurement and the hem has somewhere stable to rest. It takes a minute and it explains why one length works on you and another never does.

Waistbands

Macro of a bonded swim short waistband with an internal drawstring emerging through two eyelets

A bonded flat waistband with the drawstring emerging through two eyelets. No gathering, no visible stitching on the outer face, and real adjustment from the cord rather than from stretched elastic.

Three constructions, and they are not equivalent.

Bonded flat waistband with an internal drawstring is the best of the three for stretch swim shorts. The band lies smooth against the body with no gathering, the drawstring provides genuine adjustment, and there is no bulk under a fitted cover-up. It is more expensive to make, which is why it appears further up the range.

Gathered elastic is the common default. It is comfortable and it bunches fabric into small vertical folds around the entire waist, which adds visible bulk exactly where a swim short meets a tankini top or a bare midriff. It also relaxes faster than a bonded band.

Flat lace-up, board short style, uses a non-elasticated waistband closed with a cord through eyelets, sometimes with a hook or velcro fly. It is the most secure closure available and the reason board shorts stay on under wave impact. The trade-off is no give at all, so the size has to be right.

What to Wear Underneath

Lined shorts are worn on their own. Unlined shorts need a swim brief or bikini bottom underneath. Ordinary underwear is not an option: it absorbs and holds water, becomes transparent when wet, chafes badly, and takes hours to dry.

The complication is that board shorts are frequently unlined and listings do not reliably say so. Women's board shorts in particular are often sold without a liner on the assumption you will wear a bikini bottom, which is a fair assumption and an annoying surprise if nobody mentioned it.

Where a lining is present, it is usually a light mesh or a brief-shaped panel. A full mesh liner is more comfortable for swimming; a brief-shaped liner gives more coverage. Neither is a substitute for a swim brief if you want the shorts to come off separately at any point.

What to Pair Them With

Swim shorts are one of the more useful pieces in a swim wardrobe precisely because they pair with almost everything.

A tankini top gives full torso and thigh coverage with independent sizing at both ends. Many brands sell tankini sets with shorts rather than briefs for exactly this reason, and it is a genuinely practical combination.
A bikini top is the standard pairing and gives the most flexibility, since the two pieces need have nothing to do with each other.
A rash guard or swim tee covers the shoulders and back, which matters for long days in sun and is the usual surf pairing.
A one-piece worn underneath, with the shorts over the top, gives thigh coverage without a separate brief and works well if you already own a one-piece you like.

Care, and What Wears Out First

Fresh swim fabric swatch beside a chlorine-degraded one showing faded patchy surface and lost sheen

The same fabric before and after sustained chlorine exposure. The colour has gone patchy and the surface has lost its sheen, which is what elastane breaking down looks like. Stretch and recovery go with it.

Chlorine degrades elastane, and the damage is a function of how long chlorine sits in the fabric rather than how long you swam. That single fact drives most of the care advice.

Rinse in cool fresh water immediately after getting out, not at the end of the day.
Hand wash gently, never wring. Wringing distorts the knit permanently.
Dry flat, out of direct sun. UV degrades elastane and fades colour.
Never tumble dry. Heat accelerates everything above.
Mind the pool edge. The seat abrades against concrete faster than any other part, and it is usually what fails first.
Choose chlorine-resistant fabric for regular pool use. It holds shape considerably longer.

Expect one to three seasons. Woven board shorts generally outlast stretch swim shorts, simply because there is less elastane in them to degrade.

People try three sizes trying to stop swim shorts riding up. It is almost never the size. It is a plain hem finishing exactly where the thigh is widest.
HauteFlair Editorial Team

What This Means for You

Swim shorts and board shorts are different tools. Board shorts are woven, longer and lace-up, built to survive surf. Swim shorts are stretch knit, shorter and elasticated, built to swim in. Pick by what you are doing rather than by which looks better on a hanger.

Then solve the thing that actually determines whether you keep wearing them. Look for a silicone gripper or a bonded edge at the leg, and choose an inseam that puts the hem above or below the widest part of your thigh rather than on it. Those two together eliminate almost all riding up and most chafing.

Check whether they are lined, wear a swim brief rather than underwear if they are not, and rinse them in fresh water the moment you are out of the pool.

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Frequently Asked Questions

What are swim shorts?

Swim shorts are shorts made from quick-drying swim fabric, worn for swimming and beach wear. Women's swim shorts are typically cut from stretch swim knit with an elasticated or bonded waistband, and range from short boy-cut styles to mid-thigh and longer lengths. They are worn alone if lined, or over a swim brief if not.

What is the difference between swim shorts and board shorts?

Board shorts have a longer inseam, a flat non-elasticated waistband with a lace-up tie, and a tightly woven fabric with little stretch, all developed for surfing. General swim shorts are usually shorter, made from stretch swim knit, and use an elasticated or bonded waistband. Board shorts resist abrasion and stay closed under impact; swim shorts prioritise stretch and comfort.

Can you swim in women's board shorts?

Yes. Board shorts are designed for water and dry quickly. The trade-off is that the woven fabric has little stretch and the longer leg creates more drag than a shorter stretch short, so they are less comfortable for swimming lengths and better suited to surfing, paddleboarding and general beach wear.

What do you wear under unlined board shorts?

A swim brief or bikini bottom. Ordinary underwear is not designed to be wet: it absorbs and holds water, becomes transparent, chafes and takes a long time to dry. Many board shorts are unlined and the product listing does not always mention it, so it is worth checking before assuming.

Why do my swim shorts ride up?

Usually the leg hem has nothing holding it in position, and the hem is finishing at the widest part of the thigh. A bonded leg edge or an internal silicone gripper strip holds it in place. Choosing an inseam that finishes above or below the widest point also helps considerably.

How do I stop swim shorts chafing between the thighs?

Choose a longer inseam so the fabric sits between the thighs rather than the hem sitting at the contact point, and look for flatlocked or bonded seams rather than raised overlocked ones. A hem that rides up mid-swim reintroduces the problem, so hem grip matters here too.

What length should women's swim shorts be?

A short boy-cut of two to three inches suits swimming with the least drag. Four to six inches is the general-purpose range and prevents thigh chafing. Board short lengths of seven inches or more give the most coverage and the most drag. Choose the length so the hem does not finish at the widest part of your thigh.

Are swim shorts good for plus sizes?

They work well, and the variables that matter are inseam length, hem grip and waistband construction rather than size. A longer inseam prevents thigh chafing and a gripped hem stops it travelling. Check that the brand grades inseam length as well as waist, since many scale width alone.

Can I wear swim shorts with a tankini top?

Yes, and it is one of the more practical swimwear combinations. A tankini top with swim shorts gives full torso and thigh coverage with independent sizing throughout. Many brands sell tankini sets with shorts rather than briefs for exactly this reason. See the tankini guide.

Do swim shorts have pockets?

Board shorts often have a rear pocket, usually with a drain eyelet and sometimes a velcro or zip closure. Stretch swim shorts less often do, since a pocket adds bulk and holds water. A pocket without a drain hole will fill and stay full, which is worth checking.

What fabric are swim shorts made of?

Stretch swim shorts are typically nylon or polyester knit with 15 to 20 percent elastane. Board shorts are typically tightly woven polyester with little or no elastane, which is what gives them abrasion resistance and quick drying at the cost of stretch. Chlorine-resistant fabrics hold their shape considerably longer with regular pool use.

Are swim shorts see-through when wet?

Lighter swim knit can become less opaque when wet, particularly in white and pale colours. Woven board short fabric is generally denser and stays opaque. If buying online without being able to handle the fabric, a darker colour or a lined pair removes most of the risk.

How should swim shorts fit?

Close but not compressive at the waist, with the drawstring taking up the remainder rather than doing all the work. The leg should skim rather than grip. Swim fabric relaxes slightly when wet, so shorts that feel loose while dry will feel looser in water.

How do I wash swim shorts?

Rinse in cool fresh water immediately after every wear, before chlorine or salt sits in the fabric. Hand wash gently, never wring, and dry flat away from direct sun. Heat and UV degrade elastane, so never tumble dry.

How long do swim shorts last?

One to three seasons, and the seat usually goes first from abrasion against pool edges and rough surfaces. Woven board shorts generally outlast stretch swim shorts because there is less elastane to degrade. Rinsing immediately after use extends both considerably.

This article is for informational purposes only. Inseam ranges, fabric compositions and garment lifespans quoted are general working guidelines rather than industry standards, and vary between manufacturers. Always follow the care instructions on the specific garment.