One-piece swimsuits are no longer “one style fits all”. From underwire and bandeau to long sleeve, high neck and zip front designs, each cut offers a different mix of support, coverage and sun protection.

Use this guide to understand the key one-piece styles, what they are designed to do and which features to look for when you are choosing your next cossie.

1. Classic One-Piece

The classic one-piece is the swimwear equivalent of a little black dress: simple straps, a scoop or V-neckline and medium bottom coverage.

• Look: Clean lines, usually sleeveless, with either standard or adjustable straps.
• Support: Often has a shelf bra, removable cups or light lining rather than full underwire.
• Best for: Everyday swimming, holidays and anyone who wants an easy, timeless shape that just works.

2. Underwire One-Piece

An underwire one-piece is built like a bra through the bust and a swimsuit through the body, giving more structure and lift.

• Look: Cups are defined and shaped; some styles look like bra cups built into a one-piece, others hide the underwire behind a smooth neckline.
• Support: Underwire and firm underband support the bust, often in specific cup sizes (e.g. D/DD, F/G) with adjustable straps.
• Best for: Fuller busts, swimmers who like bra-like support, and anyone who wants lift and separation rather than a soft shelf bra.

Tip: When you try on an underwire one-piece, check the wire sits against your ribcage and the cups fully contain your bust without spillage or gaping.

3. Bandeau One-Piece

A bandeau one-piece is a strapless (or removable-strap) style with a straight or gently curved neckline that sits across the chest.

• Look: Clean, horizontal neckline; some have ruching, twist fronts or cut-outs to add shape and interest.
• Support: Grip tape or silicone along the top edge, internal shelf bra or hidden underwire; often comes with optional straps for extra security.
• Best for: Minimising tan lines on the shoulders and creating a balanced neckline for smaller to mid-size busts.

Tip: If you have a fuller bust, look for bandeau one-pieces that specify cup sizes, side boning and removable straps for extra support.

4. Long Sleeve One-Piece

Long sleeve one-pieces combine swimsuit shaping with rash vest coverage, protecting your shoulders, arms and upper back from the sun.

• Look: Fitted body with full-length or three-quarter sleeves; often paired with a zip-front or high neck.
• Coverage: Excellent upper-body sun protection, ideal if you burn easily or want more coverage than a standard swimsuit.
• Best for: Surfing, paddleboarding, ocean swimming and sun-safe beach days.

Tip: Choose a long sleeve suit with enough stretch and a front or back zip so it is easy to get on and off, even when wet.

5. High Neck One-Piece

High neck one-pieces lift the neckline higher on the chest, often towards the collarbone, for more coverage and a sleek, modern look.

• Look: Neckline sits higher than a standard scoop, sometimes like a halter or mock-neck; can be paired with open backs or keyholes for balance.
• Coverage: Extra coverage over the chest and upper bust, which can feel more modest and more sun-safe.
• Best for: Active swimmers and anyone who prefers not to show cleavage but still wants a stylish, sculpted shape.

Tip: If you have a fuller bust, look for high neck suits with built-in bust support inside (underwire or shelf bra) so you get coverage and lift at the same time.

6. Zip Front One-Piece

Zip front one-pieces feature a functional zipper, usually running from the neckline down towards the midriff or tummy.

• Look: Sporty and practical; zip can be worn fully up for more coverage or partly down for a more open neckline.
• Function: Makes it easier to get in and out of the suit, and lets you adjust bust coverage and ventilation.
• Best for: Long sleeve and high neck styles, nursing-friendly options, and anyone who wants adjustable coverage for different activities.

Tip: Make sure the zip sits flat and doesn’t buckle when you move; good quality zips should glide easily but stay in place where you leave them.

7. Other One-Piece Styles You’ll See

Beyond the main styles above, you will often see one-pieces described with additional features that can change the fit and feel.

• Tank / Sport one-piece: Wide straps, racerback or cross-back, built for lap swimming and support.
• Swim dress: A one-piece with an attached skirt for extra hip and upper thigh coverage.
• High-cut leg: Higher leg opening to visually lengthen the legs and create a more ’80s-style silhouette.
• Wrap-front or ruched: Diagonal wraps and ruching across the tummy to add shape and gentle midsection camouflage.

You can mix and match these features with underwire, bandeau, long sleeve, high neck or zip front details to get exactly the blend of support, coverage and style you want.

8. How To Choose the Right One-Piece for You

With so many one-piece styles, it helps to start with how you plan to use your swimmers and what matters most to you.

• For maximum support: Look for underwire, wide straps, firm lining and cup-specific sizing.
• For minimal tan lines: Choose bandeau or low-back one-pieces, ideally with removable straps.
• For sun protection: Long sleeve, high neck and zip front suits in UPF fabric offer the best upper-body coverage.
• For movement and sport: Tank or racerback styles, often with high necklines and secure straps, stay put during active swimming.

Combine style (underwire, bandeau, long sleeve, high neck, zip front) with the right size and fabric, and a one-piece can give you support, coverage and confidence in a single suit.