One-Piece, Bikini or Swim Shorts in 9 Best Swimsuit Sewing Patterns

Swimsuit shopping is the fitting room nobody enjoys: the top fits and the bottom does not, or the only cut in your size comes in a print you would never wear. Sewing your own takes very little fabric and no zippers, and a handmade swimsuit can fit better than a store-bought one. Useful swimsuit sewing patterns come with a detailed size chart, a fabric list and instructions or a video for the elastic.

This is a family roundup rather than a women-only list: six patterns for women, from a bow-tie one-piece in seven sizes to a halter monokini with cutouts, then a girls suit, kids swim briefs and woven swim shorts for men. Swimwear depends on its materials more than most garments, so after the cards come swim fabric, lining, elastic, needles and stitches.

Swimsuit Sewing Patterns from One-Pieces to Swim Briefs

Patterns that their designers say are sold without instructions were dropped, and so was doll swimwear. The three Romspattern listings say little beyond the style and the paper formats, so their cards keep to what is stated.

TL;DR: Swimwear for the whole family: a bow-tie one-piece in XS to 3XL, the Stella suit in XL and 2XL, a halter bikini, a striped vintage suit with mesh, a cutout monokini, the lined Diana bikini, a girls swimsuit, kids swim briefs for 3 to 14 years and woven men's swim shorts.

• Bow Tie XS-3XL Swimsuit Sewing Pattern – Best one-piece
• Stella Swimsuit Pattern VIDEO TUTORIAL – Best plus-size swimsuit
• Romspattern Minimal Halter Bikini – Best bikini
• Romspattern Vintage Mesh Swimsuit – Best vintage one-piece
• Romspattern CoreHalo Monokini Swimsuit – Best monokini
• Diana DIY Bikini Easy Swimsuit M and L – Best bikini with video
• Girls Swim Suit – Best for girls
• Sewing Pattern Swimwear Trunk 3-14 Years – Best first swimwear
• Men's Swim Shorts Sewing Pattern PDF – Best swim shorts

Quick Comparison

Swim Fabric: Nylon or Polyester With Spandex

Swim fabric is a knit of nylon or polyester blended with spandex, also sold as Lycra or elastane, with four-way stretch and good recovery. Stella’s listing is the most specific here: four-way stretch nylon, Supplex or polyester tricot with at least 10% spandex. The kids swim briefs ask for Lycra or spandex fabric with at least 75% stretch.

Nylon blends feel soft and stretch easily. Polyester blends usually hold up better to chlorine and fading, which matters for regular pool swimming. Chlorine slowly wears out the spandex itself, and so do prolonged heat and UV exposure, so rinsing a suit in cool fresh water after swimming and drying it in the shade helps it keep its stretch.

The swim brief listing makes a point worth repeating: these fabrics are not sewn the same way as ordinary knits. A first fit test is best cut from a cheaper swim fabric rather than jersey from the stash, because jersey stretches and recovers differently.

Lining and Coverage

The listing describes Diana as a lined suit and asks for about 100 cm of lycra or biflex; it does not say whether that amount covers the lining as well. The swim brief listing gives the same amount of optional lining as main fabric, 0.25 to 0.45 m, and explains its job: swim lining, usually skin-toned, white or black, makes the outer fabric opaque and gives the inside a clean finish.

Light-colored or thin fabrics often need lining, but opacity is worth testing wet. The vintage swimsuit has a mesh insert at the midsection, which is sheer by design, so the cover is the place to check how much it shows before you choose the fabric.

Swim Elastic, Needles and Stitches

• Elastic: rubber or swim elastic made for chlorine and salt water. Ordinary braided elastic tends to lose its stretch faster in the pool and the sea.
• Elastic length: use the pattern’s cut lengths and placement marks. If none are given, test the elastic on the body and on a fabric sample rather than applying a fixed amount of stretch.
• Needle: a stretch needle is the usual choice for spandex, 75/11 for lighter swim fabric and 90/14 for heavier.
• Thread: polyester rather than cotton, which chlorine and salt water weaken.
• Stitches: a narrow zigzag or the machine’s stretch stitch for seams, or a serger. A three-step zigzag is one common way to attach elastic. A conventional straight stitch usually lacks enough stretch for swimsuit seams.

The Swim Shorts Work Differently

The men’s swim shorts are the one woven pattern in the list, drafted for polyester, nylon, quick-dry fabrics or woven swimwear blends. The listing calls for an elastic band for the waistband, a drawstring cord and two optional eyelets rather than swim elastic around the edges. Read the seam allowance note before cutting, since allowances may need to be added; more pairs are in the shorts sewing patterns roundup.

FAQ: Sizes and Stretch in Swimwear

Which swimsuit patterns for women here go to plus sizes?

The bow-tie one-piece runs from XS to 3XL, and Stella is drafted only in XL and 2XL. Diana comes in M and L, and the Romspattern descriptions do not list sizes.

How do I check the stretch percentage of swim fabric?

Mark 10 cm along the fabric, hold one mark still and stretch gently until the fabric resists. If the 10 cm reaches 17.5 cm, it stretches 75%, the minimum the kids briefs ask for. Check both directions, since four-way stretch fabric should stretch both ways.

Is there a one-piece swimsuit pattern for a first try?

The bow-tie one-piece comes with step-by-step instructions, a size guide and a guide to swimwear fabrics, and Stella’s designer calls it easy for beginners. The girls suit adds three fitting videos to a photo tutorial.

Test a Scrap Wet and Stretched Before Cutting

Before cutting the suit, sew a short seam on a doubled scrap of the chosen fabric and lining, then stretch it hard. If the thread breaks or the seam waves, change the stitch width or length. Then wet the scrap and hold it up to the light: if the color shows through, plan a lining or pick a darker fabric.

It takes one scrap and catches the two problems that are hard to fix once a suit is sewn. The same check suits every one of these swimsuit sewing patterns except the woven shorts, and a loose top from the tops and blouses section makes an easy cover-up for the beach.

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