A swimsuit for your body shape comes down to three lines: where the leg opening sits, how the neckline is cut, and where the straps go. Each is an edge the eye follows. Horizontal edges read as width, vertical and diagonal ones as length, and every shape needs them in different places. A fourth question, torso length, decides whether a one-piece will fit at all.
Find your shape first with three measurements in the Body Shape Calculator, or compare all five in what body shape am I.
The three lines
The leg opening. A high leg, cut up toward the hip bone, continues the line of the leg and makes it look longer. A low, straight leg, as on boy shorts, draws a horizontal line across the thigh. A mid-height leg sits in between and is the easiest all-round choice.
The neckline. V-necks and plunges draw a vertical line down the center. Scoop necks open the chest more gently. Bandeaus and straight-across tops draw a horizontal line across the bust, which adds width on top. One-shoulder styles add a diagonal.
The straps. Halter straps angle in from the neck and make the shoulder line look narrower. Straps set wide at the shoulder edge, or a straight bandeau, do the opposite. Racerbacks pull the line toward the center at the back.
Horizontal edges add width where they fall. Diagonals and verticals add length.
Swimsuits by shape
| Shape | Goal | Top | Bottom or leg | Good one-piece features |
|---|---|---|---|---|
| Hourglass | Support and a waist | Underwire or molded cups, V or sweetheart | Mid to high leg | Waist seam, belt or ruching |
| Pear | Width on top | Bandeau, wide straps, color or ruffles | Plain, darker; high leg | Detailed bodice, plain lower half |
| Rectangle | Shape, or a sleek line | Ruffles, twists, triangle | Side ties, high leg | Cut-outs at the waist, or a clean scoop-back |
| Inverted triangle | Width below | Halter or racerback, plain | Ruffles, ties, pattern | Plain top, patterned bottom |
| Apple | Length through the middle | V or scoop with support | High leg | Ruching, wrap front, side panels |
A few notes behind the table:
Hourglass. Support matters most if your bust is full: look for swimsuits sold by bra size rather than S, M, L. A waist seam or tie keeps a one-piece from hanging straight from the bust.
Pear. Separates help more than any cut, because they let you buy the top and bottom in different sizes. A bottom with a slightly higher rise and a leg line at the hip bone avoids a horizontal edge across the fullest part of the thigh.
Rectangle. Two routes, as with clothes: add curves with ruffles, side ties and cut-outs, or wear a clean, sporty one-piece that suits the straight line.
Inverted triangle. The reverse of the pear: keep the top plain and the straps angled in, put pattern and volume below. Separates help here too.
Apple. Ruching or a wrap front breaks up the surface over the middle; a tankini lets the top hang past it. A firm fabric holds its shape better than a thin one.
Torso length: the fit problem nobody mentions
A one-piece has a fixed length from shoulder to crotch, and torso length is not part of a dress size. With a long torso, a one-piece pulls: the straps dig in, the neckline drops and the leg openings ride up. With a short torso, it bunches at the waist and the straps slide off.
Three fixes, in order of ease: adjustable straps, a one-piece sold in a long-torso size, or separates. A tankini or a bikini has no fixed shoulder-to-crotch length at all. The long torso or long legs guide shows how to check yours in a minute.
Support and fabric
Fabric weight matters as much as cut. A thicker, firmer swim fabric smooths and holds; a thin one shows every seam underneath it. Lined suits sit better than unlined ones on any shape. If your bust is larger than average for your band size, look for suits with underwire or molded cups and adjustable straps, whatever your shape.
Color follows the same rules as clothes: put stronger color where you want attention, darker or plainer color where you want less. Your own palette is in the color season quiz.