The most flattering one piece swimsuit is the one built for your shape and the job you need it to do. A wrap or ruched front draws the eye in at the waist. A square neck or wide straps gives more support. A colour-block panel or a side cutout adds curves to a straighter frame. A swim dress or skirted style gives extra coverage over the hips and thighs. This guide covers every main style of women's one piece swimwear and who each one suits. It also covers UK sizing, getting the fit right and how to style a swimming costume from the pool to the bar. Every pick below is in stock now at Fashionfitz.
Shopping right now? Go straight to our full one piece swimsuits collection.
Quick Picks: The Best One Piece Swimsuits at Fashionfitz
- Best all-rounder: Color Block One Piece Swimsuit, £22.24. Made from 82% polyamide and 18% elastane, with adjustable straps. Comes in black or navy, sizes S–2XL.
- Best for a defined waist: Crossover Colorblock Cutout One Piece, £20.75. A crossover V plunge with a waist cutout, in rose red, sizes S–2XL.
- Best for bust support without wires: Black Crisscross Back V-Neck One-Piece, £26.54. It has a twist-ruched front and padded cups.
- Best for more coverage: Ruffled Lace Trim V-Neck Swim Dress, £39.62. Tummy-control fit, with short sleeves and a skirted hem.
- Best for holidays: Halter Monokini with Floral Beach Cover Up, £34.71. Two pieces in one buy.
- Best on a budget: Ribbed Knit One Piece, £19.66. A sage green ribbed knit with adjustable straps.
Why Choose a One Piece Swimsuit?
A one piece swimsuit (also called a swimming costume, bathing suit or maillot) is the most versatile swimwear you can own. It stays in place when you swim lengths, play with the kids or jump off a boat. It gives the midsection a smooth line without the gap a bikini leaves. You can also wear it as a bodysuit with shorts or a sarong, so one swimsuit covers the beach, the pool and lunch afterwards.
One-pieces have also moved a long way from the plain black racer. Cutouts, plunging necklines, textured fabrics and colour-blocking mean you can choose coverage or statement, or have both in the same suit.
How to Choose the Most Flattering One Piece for Your Body Shape
Body shape guides are a starting point, not a set of rules. Wear what makes you feel good. That said, these are the style details that help each shape the most:
Hourglass (balanced bust and hips, defined waist)
Show off the waist. Wrap fronts, crossover necklines and belted or tie-side styles all work. Choose a suit with real bust support, such as padded cups, wider straps or a halterneck. The Crossed Back Floral Print Asymmetric Knot One Piece (£25.46) works well here because its knot sits right at the waist.
Pear (hips wider than shoulders)
Draw the eye upward. Choose detail at the neckline, such as a halter, one shoulder, ruffles or a bright top half, and keep the bottom half darker and simpler. A medium or high leg cut lengthens the legs. Try the Black Floral Cutout One-Shoulder One Piece (£22.88). Its asymmetric neckline and beaded drawstring keep the focus up top.
Apple (fuller midsection)
Look for ruching, twisting or wrap panels across the tummy, plus a V-neck to lengthen the torso. A swim dress or a suit with a skirted hem adds extra coverage. The Crisscross Back V-Neck One-Piece has a twist-ruched front. The Ruffled Lace Trim Swim Dress is cut with tummy control.
Straight / athletic (shoulders, waist and hips similar)
Create shape with cutouts, colour-blocking and asymmetric lines. A side cutout or a contrast panel gives the look of a waist. The Crossover Colorblock Cutout and the Blue Crossover Cutout One-Piece (£25.99) are both strong choices.
Fuller bust
Prioritise support over everything else. Choose wide or adjustable straps, a square or sweetheart neck, padded cups and a supportive back. Halternecks look great but put the weight on your neck, so look for a halter with a wide neck strap. The Mist Green Square Neck A-Line One-Piece (£23.16) combines a square neck, adjustable straps and padding.
Petite or long torso
Petite women should avoid heavy ruffles and choose a higher leg to lengthen the legs. If you have a long torso, adjustable straps are essential, because they stop the suit pulling down at the shoulders. Wrap and crossover styles also tend to give more room in the body length.
Shopping for curves? Our plus size swimwear guide covers more styles in sizes up to 2XL and beyond.
One Piece Swimsuit Styles Explained
- Classic scoop or square neck: a timeless shape with easy support, good for swimming lengths.
- Plunge / V-neck: lengthens the torso and flatters most bust sizes, especially when it has a crossover or wrap front.
- Halterneck: lifts the bust and shows off the shoulders. See the Corded Flower Texture Halterneck (£21.62) for a textured take.
- One shoulder: an easy statement that draws the eye upward.
- Cutout / monokini: a one-piece with open panels at the waist, sides or back. It's the halfway point between a bikini and a swimsuit. Try the Black & Pink Crossed Cutout Backless Monokini (£24.00).
- Colour-block: contrast panels that shape the figure visually. They also hide any pull of the fabric over curves.
- Textured (ribbed, corded, crinkle): more forgiving than flat Lycra and a strong trend right now.
- Swim dress / skirted: the most coverage, with a built-in skirt over the hips. We cover these in detail in our swim dresses guide.
UK Sizing and Fit: How a One Piece Should Feel
Swimwear fits tighter than clothing on purpose, because fabric relaxes when it's wet. Use these checks in the fitting room or at home:
- Shoulders: straps should stay put without digging in. If they dig, the suit is too short in the body. Size up or loosen adjustable straps.
- Bust: no spilling over the cups and no gaping. Raise your arms. If the cups move, the support is wrong.
- Leg line: the leg opening should lie flat against the skin. Riding up suggests the torso is too short. Cutting in suggests the suit is too small.
- Bottom: full coverage should stay in place when you sit and squat.
- Between sizes? Go by your bust if you need support, and by your hips if you want coverage. Check each product's size chart, because cuts vary from style to style.
Most of our one-pieces come in UK sizes S to XL or S to 2XL. Each product page has its own size guide. For more help, see our guide on how to choose a swimsuit that feels right.
Fabric: What to Look For
Good one piece swimwear is usually a blend of polyamide (nylon) or polyester with elastane (spandex). The elastane is what gives stretch and recovery. Around 15–20% elastane gives a firmer, more sculpting hold, like the 82/18 blend in our Color Block One Piece and the 80/20 blend in the Crisscross Back One-Piece. Lower-stretch ribbed and textured fabrics feel softer and look more relaxed. Quick-dry fabrics such as the Duffel Green Color Splash One Piece (£24.99) are ideal when you go from the sea to a beach bar.
How to Style a One Piece Swimsuit: Beach to Bar
- Beach day: a one-piece, a straw hat, slides and a cover-up you can throw on. Our beach cover-ups guide has the best options.
- Pool to lunch: add high-waisted linen trousers or a wrap skirt. A one-piece makes an instant bodysuit.
- Sunset drinks: a cutout or one-shoulder suit with denim shorts, gold jewellery and a shirt worn open.
- Family holiday: a supportive square-neck or swim dress style lets you chase children all day without readjusting.
- Winter sun: pack two one-pieces. While one dries, you wear the other. They take up less room than bikini sets.
Planning a trip? See what's trending in our swimwear trends UK 2026 edit.
How to Care for Your Swimsuit So It Lasts
- Rinse in cool fresh water as soon as possible after swimming in chlorine, salt water or suncream.
- Hand wash gently with a mild detergent. Don't wring the suit. Press the water out in a towel instead.
- Dry flat in the shade. Direct sun and tumble dryers break down the elastane.
- Rotate between two suits on holiday so each one can fully recover.
- Avoid sitting on rough pool edges, which cause pilling.
Quick Questions
What is the most flattering one piece swimsuit style?
For most body shapes, a wrap or crossover front with a V-neck is the most flattering. It defines the waist and lengthens the torso. Add ruching for tummy control, or cutouts and colour-blocking to create curves.
Is a swimming costume the same as a one piece swimsuit?
Yes. In the UK, "swimming costume" or "swimsuit" usually means a one piece. Bathing suit and maillot are other names for the same thing.
Should a one piece swimsuit be tight?
It should be snug but not restrictive, because swimwear relaxes a little when wet. If straps dig in or the leg line cuts in, size up. If the fabric wrinkles or the cups gape, size down.
Which one piece is best for a fuller bust?
Look for wide or adjustable straps, padded or moulded cups and a square or sweetheart neckline. Halternecks work if the neck strap is wide.
What's the difference between a monokini and a one piece?
A monokini is a one piece with large cutouts, usually at the sides, waist or back, so from some angles it looks like a bikini. It's still a single garment.
Are one piece swimsuits better for swimming?
Generally, yes. A one piece stays in place through diving and lengths, and a closed or crisscross back adds security. For serious lap swimming, choose a scoop or square neck with a high elastane content.
Shop One Piece Swimsuits at Fashionfitz
From supportive square necks to statement cutouts, every style above is in stock with UK delivery. Browse all one piece swimsuits, or look at our swim dresses if you'd like extra coverage.
