Table of Contents
- Why Plus Size Swimwear Fit Matters More Than Size
- How to Measure for Swimwear: A Simple 3-Step Method
- Best Plus Size Swimwear for Tummy Control
- Supportive Swimwear for Curvy Women: What to Look For
- One-Piece, Tankini or Bikini Separates: Choosing Your Shape
- Fabric, Chlorine and Colour: Making Swimwear Last
- Resort Wear, Cover-Ups and Poolside Style
- Conclusion
- Frequently Asked Questions
Last Updated: September 14, 2026
Why Plus Size Swimwear Fit Matters More Than Size
Shopping for plus size swimwear in 2026 comes down to fit, not the number on the tag. A size 18 behaves differently from one design to the next, and that gap is where most online shopping disappoints, especially with "size-inclusive" labels that simply scaled up a straight-size pattern.
What separates swimwear that works from swimwear that sits in the drawer comes down to three things: where the seams sit, how the fabric recovers, and whether the bust is actually supported rather than just covered. Get those right and the size number becomes almost irrelevant.
Below: how to measure properly, which silhouettes suit which shapes, and how to make a swimsuit last more than one summer. 🩱
How to Measure for Swimwear: A Simple 3-Step Method
Learning how to measure for swimwear takes five minutes and saves you a return. You need a soft tape measure, a mirror, and a well-fitting bra or no bra.
Measure over bare skin or light clothing, keep the tape level and snug but not tight, and write the numbers down.
Bust, Waist and Hip: What to Measure and Why
Bust is measured around the fullest part of your chest, tape parallel to the floor. Waist sits at your natural waistline, the narrowest point above your belly button, not at the top of your jeans. Hip is the widest point around your seat, usually 20cm or so below the waist.
Each measurement matters for a different part of the swimsuit. Bust determines cup and strap fit, waist affects how a one-piece sits through the middle, and hip decides whether bottoms ride up or stay put. Bust and hip landing in different sizes is normal.
Reading a Size Chart When You Sit Between Sizes
Between two sizes, size up for one-pieces and structured tankinis, since swim fabric has limited stretch and a tight fit pulls at the seams. Size down for high-waisted bikini bottoms, which rely on a firm hold to stay in place.
A quick rule that works well in practice:
- Bust and waist in different sizes → follow the bust for tops, waist for bottoms
- Hip measurement larger than the chart's top size → look for adjustable tie sides
- Torso longer than average → choose tankinis over one-pieces for a better length match
Best Plus Size Swimwear for Tummy Control
The best plus size swimwear for tummy control uses structure, not compression. Ruching, drawstrings and lined panels smooth the midsection by redistributing fabric, while heavy compression fabrics roll down and dig in after an hour in the water.
Look for a double-lined front panel and side ruching rather than an all-over tight fit. The Sea Green Drawstring Tummy Control Mix-and-Match Tankini is a good example: the adjustable side drawstring sets your own coverage, and as a two-piece the top and bottom can be sized independently.
Sea Green Drawstring Tummy Control Mix-and-match 2pcs Tankini Swimsuit
Ruching, Drawstrings and Panels That Actually Work
What to look for:
- Side ruching gathers fabric vertically, breaking up the silhouette and hiding softness without squeezing
- Drawstring sides let you adjust length and tension on the spot, useful if you're between sizes
- Front-lined panels add a smooth layer without bulk, and hold their shape better in chlorine than single-layer fabric
- High-waisted bottoms cover the lower tummy and stay put when you swim, unlike low-rise cuts
What most guides miss: tummy control works best when the bust is properly supported. If the top pulls forward, the whole swimsuit shifts and the smoothing effect disappears.
Supportive Swimwear for Curvy Women: What to Look For
Supportive swimwear for curvy women needs three features: underwire or a built-in shelf bra, adjustable straps, and a band that sits firmly under the bust. Without those, a swimsuit might look right in a photo but fail the moment you move.
Underwire gives the most lift and separation, suiting fuller busts; a shelf bra or moulded cup is a lighter option for smaller busts. Adjustable straps matter more than most people realise, because a fixed strap either digs in or slips off depending on torso length.
One-Piece, Tankini or Bikini Separates: Choosing Your Shape
One-pieces suit a simplified look with full coverage through the middle. Tankinis work best if you're long in the torso or want to mix sizes. Bikini separates give the most control over fit, since you can pick a different size for top and bottom.
If you're between sizes or your top and bottom measurements differ, separates are usually the safer buy. For tummy control with a one-piece look, a swim dress bridges the gap.
Black Solid Color Ruffle Detail Crossed Cutout Slim Tankini 2pcs Swimsuit
The Black Ruffled Short Sleeve Lace Trim V Neck One Piece Swim Dress is a strong pick. The short sleeve and V neck keep it cool, the lace trim adds detail without fuss, and the swim dress cut gives coverage through the hip.
Style |
Best For |
Coverage |
Sizing Flexibility |
|---|---|---|---|
One-piece |
simplified look, swimming laps |
Full torso |
Single size only |
Tankini |
Long torsos, mixed sizes |
Adjustable |
Top and bottom separate |
Bikini separates |
Custom fit top and bottom |
Minimal to full |
Highest flexibility |
Swim dress |
Tummy and hip coverage |
Full |
Single size only |
Fabric, Chlorine and Colour: Making Swimwear Last
Chlorine is the single biggest killer of swimwear. It attacks elastane (spandex) fibres, breaking the polymer chains that give a swimsuit its stretch and recovery, which is why a suit that fits beautifully in January can feel loose by March if worn in a chlorinated pool several times a week (pubmed.ncbi.nlm.nih.gov). Salt water and sunscreen are gentler but still contribute to fibre fatigue.
What the Fabric Label Actually Tells You
The fibre blend on the care label is the most reliable predictor of how a swimsuit will age:
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- Polyamide (nylon) and elastane blends, commonly around 80% polyamide and 20% elastane, balance softness, stretch and recovery, and hold shape well in chlorinated water.
- Polyester and elastane blends, slightly firmer hand-feel, excellent chlorine resistance, and the better choice if you swim laps regularly.
- PBT (polybutylene terephthalate), a premium chlorine-resistant fibre often blended with polyester, common in performance and training swimwear.
- Higher elastane content (above roughly 20%) gives a snugger, more compressive fit that resists drag in the ocean, but degrades faster in chlorine, a genuine trade-off between compression and longevity.
Swimwear marketed purely on look often uses a lower-cost blend with less recovery, while performance pieces specify PBT or higher-grade elastane. Reading the label before you buy is the best durability decision you can make.
UPF Ratings and Sun Protection
Australia has one of the highest UV exposures in the world, and swimwear is regulated as sun-protective clothing under Australian Standard AS/NZS 4399. A garment rated UPF 50+ blocks more than 98% of UV radiation, a tested rating, not a marketing claim (Sun protection | National Cancer Prevention Policy Skin Cancer Statistics and Issues).
Two practical points most guides skip:
- Stretch reduces protection. A fabric tested at UPF 50+ relaxed can drop significantly when stretched tight across the body, so a snug fit is not automatically a safer fit for sun protection.
- Wet fabric offers less protection than dry. Water reduces the UV-blocking capacity of most textiles, so a lighter or thinner swimsuit is not a substitute for sunscreen on exposed skin.
A Care Routine That Actually Extends Lifespan
Rinsing in cool fresh water immediately after every swim, before the suit goes in a bag, does more for lifespan than any specialty detergent. It takes ten seconds and removes most chlorine, salt and sunscreen residue before it bonds to the fibres.
A workable routine:
- Rinse in cool fresh water straight after swimming.
- Hand wash with a gentle, pH-neutral detergent (never wool wash or fabric softener, which coat the fibres and reduce stretch).
- Squeeze, do not wring. Wringing stretches elastane past its recovery point.
- Dry flat in shade. Direct sun fades colour and weakens fibres; hanging by the straps stretches them out of shape.
- Rotate between at least two suits if you swim several times a week, so each has 24 hours to recover its shape.
Sustainable Fabric Sourcing
A growing number of swimwear labels use recycled polyamide or recycled polyester, often from post-consumer plastic or discarded fishing nets, to reduce virgin-plastic use. Performance is comparable to virgin fibre in most cases, though recycled elastane remains rare because it is hard to recycle without losing elasticity. If sustainability matters, check whether the label names the recycled content and whether the piece is built to last, since durability is itself a sustainability outcome.
Resort Wear, Cover-Ups and Poolside Style
Resort wear turns a swimsuit into a full outfit, and the right cover-up makes the pool-to-lunch transition effortless. Choose a cover-up that works with your swimsuit's silhouette rather than fighting it, matching it to your body shape, not just the colour palette.
Cover-Ups by Body Shape
Most guides treat cover-ups as one-size-fits-all. They are not. Shape-specific starting points:
- Pear shape (hips wider than bust): A wrap or tie-front cover-up that cinches at the waist draws the eye upward and balances the hip line. Avoid straight-cut tunics that hang from the bust, they add visual width at the hip.
- Apple shape (fuller through the middle): An open-front kaftan or a longline shirt worn unbuttoned creates two vertical lines down the body, which lengthens the torso. Empire-line cover-ups that sit just under the bust also work well.
- Hourglass: A belted or wrap cover-up that follows the waist keeps the natural proportion visible. A sarong tied at the hip is a classic option here.
- Inverted triangle (bust wider than hips): A cover-up with volume at the hem, a flared or A-line tunic, balances the shoulder-to-hip ratio.
- Rectangle (bust and hips similar, little waist definition): A cover-up with a drawstring or belt creates waist definition that the swimsuit alone may not.
Fabric Weights and What They Do
Cover-up fabric weight determines how it behaves in heat and humidity:
- Cotton voile and cotton gauze (lightweight): Breathable, quick-drying, ideal for humid coastal days. Slightly sheer, so best over a swimsuit you are happy to show.
- Linen (mid-weight): Wicks moisture and feels cool against the skin, but creases easily. A linen shirt worn open over a one-piece is a workhorse piece.
- Rayon or viscose (lightweight, drapey): Flows well and packs down small, but loses shape when wet and can shrink if washed hot.
- Cotton-blend kaftans (mid-weight): More opaque and structured, good for resort lunches where you want fuller coverage.
A lightweight cotton or rayon sarong is the most versatile single piece: worn as a skirt, dress, wrap or head covering, it cuts down what goes in the suitcase.
Colour and Print Matching
Keep the cover-up palette tied to the swimsuit, but use contrast rather than a perfect match:
- A solid dark swimsuit (black, navy, deep green) pairs well with a neutral or patterned cover-up, the pattern adds interest without competing.
- A printed swimsuit (florals, geometrics) works best under a solid cover-up in a colour pulled from the print. A blue floral one-piece, for example, sits well under white, cream or a matching blue.
- Metallics and brights are best left as the single focal point, pair them with a neutral cover-up so the eye has somewhere to rest.
Packing Logic for a Swimwear Trip
For a trip, build the capsule around two swimsuits and two cover-ups:
- One solid swimsuit and one printed swimsuit, this covers most styling combinations.
- One neutral cover-up (works with both suits) and one patterned or coloured cover-up (adds variety).
- One sarong that doubles as a skirt or dress.
- A wide-brim hat and flat sandals to finish the poolside-to-lunch transition without changing.
This is where versatile, well-made pieces earn their place in the bag, a cover-up that only works with one swimsuit is dead weight.
Conclusion
Getting plus size swimwear right comes down to measuring properly, choosing structure over compression, and looking after the fabric once it's yours. Size is just a starting point; the fit details do the real work.
At Sandee Rain Boutique, we design for real bodies with inclusive sizing, buttery-soft fabrics and ethically made pieces, backed by 813 reviews and a 96% positive rating. Our swimwear range includes the Black Ruffled Short Sleeve Lace Trim V Neck One Piece Swim Dress, the Sea Green Drawstring Tummy Control Tankini and more, all built for comfort and coverage that lasts.
SHOP NOW and find a swimsuit that fits the way it should.
Frequently Asked Questions
What swimwear is most flattering for a plus size figure?
Styles with a defined waist and structured bust tend to flatter most. A swim dress with a ruffled hem skims the hips and thighs, while a tankini with a tummy control panel lets you mix sizes between top and bottom. High-waisted bikini bottoms with a wide waistband also create a smooth line. The key is a supportive silhouette that follows your shape rather than compressing it, plus adjustable straps so you can fine-tune the fit. Try two or three cuts and keep what feels secure when you move.
What features should I look for in plus size swimwear for extra support?
Look for an underwire or a built-in shelf bra, wide adjustable straps, and a firm underbust band that stays flat when you raise your arms. Power mesh panels across the tummy add control without stiffening the whole garment. Chlorine resistant fabric with a polyamide and elastane blend holds its shape across a season of swimming. Check the size chart for underbust girth, not just bust, because that measurement decides whether the band will stay put.
Are there specific fabrics that provide better comfort for plus size swimwear?
A blend of polyamide and elastane, often around 82% and 18%, gives four-way stretch that moves with you and recovers its shape after swimming. It also resists chlorine better than polyester-only fabric, so colours and prints hold up longer. Lined fronts add coverage and stop lighter colours going sheer when wet. Rinse the swimsuit in cool water after every wear, dry it in shade, and avoid hot spas if you want the elastane to last.
How do I choose the right swimsuit for my body shape?
Start with how to measure for swimwear: bust at the fullest point, natural waist, and hips at the widest point. If your hips are wider than your bust, a swim dress or high-waisted separates balance the line. If your bust is fuller, prioritise underwire and adjustable straps. If your middle is your focus, a tummy control tankini or a ruched one-piece works well. Order your largest measurement and size up if you sit between sizes.
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