10 Best One-Piece Swimsuits of 2025, Tested by Swimmers and Textile Experts

Sizes: 10–16 | Materials: 69% nylon and 31% Lycra spandex | Colors: 6

This swimsuit aced our tests for holding up to seawater, UV light, chlorine and sweat. Not only is it durable, but testers also rated this suit as having more slimming power than others we tested. Some testers noted that this suit minimized their stomach and that they liked the lift the built-in underwire provided. This suit comes in up to six colors depending on the retailer, but we also love the brand's Sanibel Swimsuit, which comes in a variety of fun prints and bold colors.

The price is a bit high and the size range is limited, but if it's available in your size and in your budget, then we love this suit for it's effective tummy-controlling.

RELATED: The Best Tummy Control Swimsuits

Sizes: XXS–XXL and 16 Plus–26 Plus | Materials: Nylon and spandex | Colors: 29

This high-neck one-piece has over 25,000 five-star reviews on Amazon, so our experts put it to the test on 10 real women of different body types and ages. While our pros noted the suit may not be the absolute best quality, it's an incredible value and every tester rated it as flattering. Many of our testers also found the swimsuit to be slimming, comfortable and supportive.

We also like that this suit has padded cups that can be removed and is machine washable. Plus, it's available in 29 fun colors and patterns, including neutrals, neons and animal prints.

READ OUR FULL REVIEW: Tempt Me High Neck One-Piece Swimsuit

Sizes: 0–24, classic or long torso | Materials: Recycled nylon, elastane, Repreve®, elastane lining | Colors: 12

Avoid the strap tan lines with this strapless and ruched swimsuit. Earning perfect marks in every category by one of our GH testers, this one-piece bandeau has all the features we love in a high-quality swimsuit: The fabric includes built-in UPF 50 sun protection, you can add straps for more support and the cup padding is removable.

A tester noted that you cannot dive head first into the pool without the straps on for this suit, but the strapless design otherwise stayed in place (so maybe opt for another bathing suit if you plan to dive or surf!).

One GH editor loves the simple, ruched design of this long-lasting suit and has worn it summer after summer. "It's classic and ultra flattering... timeless really," said another tester. We also like that the size range is extensive and includes regular and long torso options so that you can find your perfect fit.

Sizes: XS–XXL | Materials: Chinlon and spandex | Colors: 29

When you're in need of a swimsuit ASAP, Amazon Prime's fast and free shipping has got you covered. CUPSHE is one of our favorite swimsuit brands on Amazon for its affordable price, great quality, extensive size range and variety of color options. This one-piece swimsuit has a deep-V neckline, high-cut bottom and ruched stomach for a stylish, tummy-control design.

The straps are thin, which could feel less supportive for larger chests or dig into the skin, but they are adjustable and one five-star reviewer on Amazon wrote that the fabric itself was thick and the suit was supportive in the chest area. Our GH testers also loved CUPSHE suits: "I've worn swimsuits that cost three times as much as this one, but I'm always reaching for it on a pool day," said one tester who tried a CUPSHE bikini.

Sizes: XS–3X, classic or long torso | Materials: Spandex and nylon (or recycled nylon) | Colors: 16

In our experts' roundup of the best swimsuit brands, Andie was named the best brand for one-piece swimsuits, though they are on the pricey side. Like other suits from this company, Andie's Almafi One Piece offers classic and long-torso size options to an already extensive size range (XS–3X). That means if you're 6 feet tall, you can rock a one-piece swimsuit without needing to size up (the suit will actually fit well without looking baggy or digging into your skin!). You can even choose the coverage level you want for the bottom.

One of our GH analysts reported that this swimsuit has a slightly compressive material that's comfortable and less restrictive than some other smoothing styles she has tested. There is no underwire, but the suit comes with removable cups and adjustable straps for support.

We also love that you can choose from 16 bright colors and patterns that vary between six types of fabric (eco nylon, ribbed, flat, solid ribbed, textured weave and eco ribbed).

Sizes: 8–34 | Materials: 82% nylon and 18% spandex | Colors: 15

It's hard to beat the size range of this swimsuit, which is available in sizes 8 to 34 so that you can find your perfect fit. Featuring a longer panel of material in the front section, this one-piece swimsuit is designed to have the appearance of wearing a sarong. Cute yet functional, the sarong portion adds extra coverage and the front stomach area is lined with Power Mesh fabric for tummy control and smoothing.

The elastic under band and built-in cups provide support without traditional metal underwire. One tester with DD-cups was impressed by the supportive feel of a Swimsuits for All top that had no underwire. Keep in mind that many online reviewers wrote that the suit ran small, so you may want to size up.

Sizes: 2–20/22, regular or long torso | Materials: polyamide, elastane, polyurethane, polyester | Colors: 7

Be a pop of color on the poolside or at the beach with this vibrant halter-neck swimsuit from Boden. We love this retro design with color blocking that makes this suit a unique standout among a sea of floral and tropical patterns.

This bathing suit is constructed with silicone tape at the neckline to keep the straps in place and flexible boning at the side seams. Our pros in the Textiles Lab said the suit is slimming without being overly structured or squeezing you too hard. We also love that it's machine washable for easy cleaning.

The general thoughts on sizing were mixed among our analysts and online reviewers, with some finding it to fit true to size and others who said it ran small. Be sure to check the exact measurements in Boden's size guide, but the brand does offer returns as long as the hygienic strips are still in place.

Sizes: 0–24, regular or long torso | Materials: Recycled polyamide and elastane | Colors: 12

Summersalt is a favorite brand among our editors, and the Sidestroke one-shoulder bathing suit is one of its most popular styles (it has sold out dozens of times!). It is made of a compressive fabric that shapes the bodice without feeling too tight. The design also features a colorful, diagonal pleated effect across the front and a unique cut-out back. Plus, there are tons of sizes (including a long-torso option for taller folks) and color variations to choose from.

One thing to be aware of is the suit's lack of lining or cups for modesty, but some of our analysts with larger bust sizes said the suit felt secure and stayed in place while wearing.

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Sizes: 6–18; regular and D–DDD cups; regular, petite, plus size, long torso and long torso plus | Materials: Nylon and spandex | Colors: 3

This sleek one-piece swimsuit from Lands' End was rated as "most flattering" by product testers in a recent swimsuit test, thanks to the firming, slimming fabric. In our Lab tests, the fabric held up to repeated washing and performed well in our colorfastness evaluations (although the suit only comes in black, navy or green). This means the suit should be long lasting and withstand washing, chlorine, saltwater, UV rays and wear summer after summer. "Hands down, Lands' End offers the best bathing suits I've been able to find!" one tester said.

While the smallest size starts at a 6, the size range is impressive, going up to a size 18 with regular, petite, plus size, long torso and long torso plus options. Additional sizes are available up to 24 when you select plus size or long torso plus, and you can pick between regular, D, DD and DDD cup sizes, which makes it perfect for women with larger busts.

RELATED: The Best Swimsuits for Large Busts

Sizes: 20–40 | Materials: Polyester and spandex | Colors: 12

Whether you're training for a triathlon, want to swim laps for an exercise that's easy on the joints or your teenager needs a new competitive suit, this pick is one of our favorite styles from Speedo, a trusted brand for water sports. Its ProLT swimsuit is made with durable fabric that Speedo claims is resistant to chlorine, sand and sunscreen.

The fully lined suit comes in a few solid color options and the compressive material is supportive without the need for underwire or padding. We love that this suit is designed to stay in place when diving into a pool, running along the sand or doing any physical activity.

Keep in mind that athletic swimsuit's sizing is different than normal swimsuits' sizing. Check the size guide for your measurements, but here's an example: My waist is a size 25, so my measurements on the Speedo size guide would slot me for a size 28.

However, this pick is constructed with compression fabric to benefit athletes' performance and decrease resistance in the water, so it does run on the smaller side. I wear a size 30 for casual laps — and even that can feel tight to a non-competitive swimmer. If you plan to wear this suit for more casual activities, we recommend going up by a size or two.