How to fix a bathing suit that is too small

Too-small bathing suits cause discomfort and ruin beach days. Let’s learn how to adjust, stretch, and alter your too-tight bathing suit for a perfect fit.

Quick links:

Quick fixes

Alter the swimsuit

Specific solutions for different styles

How to fix different fabric types

Quick fixes

A small bathing suit doesn't always require alteration. Try these simple, no-sew solutions to improve the fit of your swimwear:

Adjust swimsuit straps and ties. Many swimsuits feature adjustable straps or ties. Loosen shoulder straps on one-piece swimsuits or bikini tops for a more comfortable fit. Adjust the knots to sit higher on the hip bone for bikini bottoms with side ties for better coverage. Some one-piece bathing suits have ruching or gathering that can be loosened for extra room.
Remove padding. If your swimsuit has removable padding, take it out for more space. This works well for tight bikini tops or one-piece suits with built-in bras.
Wear it damp. Put on your bathing suit while it's slightly damp. The moisture stretches the fabric and molds to your body shape. As it dries, it may retain a better fit.

If quick fixes don't solve the problem...

Alter your small swimsuit

For those with basic sewing skills, minor adjustments can be made at home:

Add fabric to problem areas such as the sides of the bottoms, under the bust, or along the back.
Use stretchy, chlorine-resistant fabric that matches your swimsuit.
Attach new fabric using a stretch stitch or zigzag stitch on a sewing machine.
Always test on a small area first and adjust as needed.

Swimsuit alterations often require precision and specialized knowledge.

Complex alterations. Major size changes, reshaping one-piece suits, or extensive modifications to bikini tops often demand expert skills.
Delicate fabrics. Swimsuits with metallic threads or intricate patterns need special handling to avoid damage.
Swimsuits with built-in support. Suits with molded cups or internal structures require specialized knowledge to preserve their function.
Expensive or designer swimwear. High-end pieces deserve professional care to maintain their quality and value.
Time constraints. Professional tailors can complete alterations quickly if you are in a hurry before a vacation.

Professional tailors have the expertise, tools, and experience to handle tricky fabrics and complex alterations. They can often rescue swimsuits that seem beyond repair, potentially saving you money in the long run. They can also guarantee a proper fit, which is important for both comfort and appearance in swimwear.

Specific solutions for different styles

Different types of swimsuits require different approaches.

One-piece bathing suits

One-piece swimsuits often need torso lengthening. Add a fabric strip at the waist to provide more vertical coverage. Insert side panels to increase the width. Extend leg openings with additional fabric to provide more coverage or a better fit for longer legs.

Bikini tops

For bikini tops, add a piece of fabric to the band around the ribcage. Extend the cups with triangular inserts to increase bust coverage and help with cup size issues. Replace thin straps with wider, adjustable ones to improve support and allow for a more customizable fit.

Bikini bottoms

Improve women’s swim bottoms with fabric panels added to the sides to increase overall coverage and enhance the fit around the hips. Extend the waistband for high-waisted bottoms to provide more tummy coverage. Insert a modesty panel in the front or back to address coverage concerns.

Tankinis

Lengthen tankini tops with a fabric strip added to the bottom hem for more torso coverage. Widen the silhouette with side inserts to get a better fit around the midsection. Adjust existing straps or add new ones to improve support and comfort.

Board shorts and swim trunks

Extend the waistband of board shorts and swim trunks with elastic or additional fabric to accommodate different waist sizes. Add side slits to increase hip room, mobility, and comfort. Attach a fabric strip to the bottom hem to lengthen the shorts—this is especially useful for taller individuals or those who prefer more leg coverage.

How to fix different fabric types

Different swimsuit fabrics require specific alteration techniques because of their unique compositions and properties. Here's how to approach different fabric types:

Nylon and spandex blends
Polyester blends
Textured fabrics
Lined swimsuits
Natural fibers
Metallic or sequined fabrics
Chlorine-resistant fabrics

Nylon and spandex blends

If you sew by hand, use a stretch stitch or a small, tight zigzag stitch. With a sewing machine, choose a stretch stitch or a narrow zigzag stitch. A ballpoint needle prevents fabric damage. These blends are heat-sensitive. Iron them carefully on low heat or use a pressing cloth to protect the fabric.

Polyester blends

Polyester swimsuit fabrics respond well to standard sewing techniques. A universal needle works fine, but a Microtex needle provides cleaner stitches. These fabrics tolerate higher iron temperatures than nylon blends.

Textured fabrics

Swimsuits with textures such as ribbing or jacquard patterns require extra care. Align patterns when adding fabric. Use a walking foot on your sewing machine to prevent layers from shifting. Hand basting before machine sewing lets you maintain fabric alignment.

Lined swimsuits

Many suits feature a second layer of fabric for modesty or support. Treat each layer separately when altering. Secure both layers together at the seams to prevent shifting. Use lightweight lining fabrics for additions to maintain the original drape and feel.

Natural fibers

Cotton or bamboo blend swimsuits stretch less than synthetic fibers. Allow for more ease when altering these fabrics. Pre-wash any new fabric to prevent shrinkage mismatches. These fabrics often require a higher thread tension on your sewing machine.

Metallic or sequined fabrics

Decorative swimsuits need delicate handling and hand sewing is the best method for most alterations. Use a leather needle for metallic fabrics to prevent snagging. Remove sequins from the seam allowance before sewing, then reattach them by hand.

Chlorine-resistant fabrics

These fabrics maintain their stretch and color longer. Standard polyester thread deteriorates in chlorine, so use a chlorine-resistant thread for alterations. These fabrics often require a looser stitch to maintain their stretch properties.

How to prevent future issues

Proper care and smart shopping help you avoid too-small swimsuits.

Buy the right size. Check the size chart before you purchase. Swimsuit sizes differ between brands. Try on several sizes to find your best fit. When in doubt, select a larger size for comfort.
Wash with care. Clean your swimsuit in cool water. Hot water damages synthetic fibers and causes shrinkage. Remove excess water gently—don't wring or twist the fabric. Lay flat to dry away from direct sunlight.
Store correctly. Keep swimsuits flat or hang them to maintain shape. Avoid folding, which creates creases in stretchy fabric.
Choose adjustable styles. Pick swimsuits with adjustable straps. These adapt to your body and prevent wardrobe malfunctions.
Think about fabric type. Synthetic fabrics such as nylon and spandex blends offer more stretch. Natural fibers shrink more easily.
Look for extra fabric. Swimsuits with ruching or excess fabric provide room for movement and fit changes.

Choose high-quality SwimZip swimwear

SwimZip's swimwear is true to size and the materials resist shrinking and stretching. It features durable, quick-drying fabrics made from nylon and spandex, with a polyester lining for comfort and support. Our high-quality swimwear provides long-lasting UPF 50+ sun protection.

From men's swim trunks and women's swimwear to kids' sunsuits, sun hats, rash guards, and accessories, we’ve got you covered.

As one of the most trusted UPF 50+ brands, SwimZip is committed to keeping you and your loved ones safe from harmful UV rays.

Mothers with their kids in matching SwimZip sun-protective swimwear—How to fix a bathing suit that is too small

Swimsuits FAQ

Do swimsuits stretch with wear?

Swimsuits stretch over time with regular use. The amount of stretch depends on the fabric composition and how often you wear it. Proper care, such as rinsing after use and avoiding hot water, maintains the suit's original shape.

How do you fix bathing suit bottoms that are too big?

If your bathing suit bottoms are the wrong size, try these fixes for a better fit:

Sew the side seams tighter
Add an elastic band to the waistband or leg holes
Use hidden safety pins
Create darts or pleats to remove excess fabric

These methods help achieve a snugger, more flattering fit.

Do bathing suits stretch when wet?

Most bathing suits stretch when wet. Water causes the fabric fibers to relax and expand. The suit usually returns to its original size when dry. Repeated stretching while wet can permanently affect the suit's shape and fit.

How often should you wash your bathing suit?

Wash your swimsuit after every wear, even if you don't go in the water. Sunscreen, sweat, and oils can break down the swimsuit’s material. Rinse your suit in fresh water with mild soap to remove chlorine, salt, and other chemicals.

Will my favorite swimsuit shrink in the dryer?

If you put your favorite swimsuit in the dryer, it might shrink and lose shape. Heat and the rough surfaces of the dryer damage delicate fibers. Always air-dry your swimsuit.

How to make your swimsuit last longer?

To extend the life of your swimsuit, rinse it in clean water after each use, especially after exposure to chlorinated or salt water. Hand wash with mild soap and cool or lukewarm water, avoid rough surfaces, and air dry. Store swimsuits properly between wears and rotate garments to avoid excessive use.