How To Find The Right Fit: The Modern Trunk
Finding the right fit in short swim trunks comes down to three measurements: waist, inseam, and rise. This guide covers all three for the Bather Modern Trunk — a tailored, 4.5-inch inseam swim trunk built with a recycled nylon shell and an exclusive quick-dry mesh liner.
Start With The Waist
The Modern Trunk uses an elasticized waistband with an internal drawstring. The internal placement keeps the exterior clean and contributes to the trunk's sharper profile.
To size, match the waist of your favourite pair of jeans to the chart below. The elasticized waistband and drawstring give you flexibility if you sit between sizes.
*All measurements in inches
| Size | XS | S | M | L | XL | XXL |
| Pant Size | 28-29 | 30-31 | 32-33 | 34-35 | 36-37 | 38-39 |
| Waist | 14.5 | 15.5 | 16 | 17 | 18 | 19 |
| Inseam | 4.5 | 4.5 | 4.5 | 4.5 | 4.5 | 4.5 |
| Outseam | 14.5 | 15 | 15.5 | 16 | 16.5 | 17 |
| Front Rise | 11 | 11.5 | 12 | 13 | 13.5 | 14 |
| Back Rise | 15.5 | 16 | 16.5 | 17.5 | 18.25 | 19 |
| Leg Opening | 12 | 12.5 | 13.5 | 13.75 | 14.75 | 16 |
The Inseam: Why 4.5 Inches
The Modern Trunk is a short swim trunk — 4.5 inches across every size. That's a full inch shorter than the Bather Classic Swim Trunk, and it's what gives the silhouette its contemporary, tailored look on the leg. Shorter inseams hit higher on the thigh, which creates a cleaner line and a more proportional silhouette when paired with the slim leg opening. The outseam scales from 14.5 inches (XS) to 17 inches (XXL), keeping the overall shape consistent regardless of where you land on the chart.
The Leg Opening
The leg opening runs from 12 inches (XS) to 16 inches (XXL) — proportioned to work with the shorter inseam. Wide enough to move and swim freely, close enough to the body that it won't flap or balloon in the water
The Rise: Front and Back
Rise is the distance from the waistband to the crotch seam. It determines how a trunk sits on the body when you're moving. The front rise runs from 11 inches (XS) to 14 inches (XXL). The back rise is longer — 15.5 inches (XS) to 19 inches (XXL) — giving coverage and preventing pulling when you bend or sit. That difference between front and back is what keeps the trunk in place when you're active, without feeling restrictive when you're not.
The Fabric: Two Premium Options
Both versions of the Modern Trunk are built from a quick-dry recycled fabric: 55% Recycled Nylon, 44% Recycled Polyester, sourced from recycled PET bottles.
The Seersucker Modern Trunk has a subtle puckered texture and a classic resort feel, available in four refined tonal stripes. The weave gives the fabric structure and breathability without added weight.
The Iridescent Modern Trunk is built from a proprietary fabric with a light-shifting sheen woven directly into the construction — not a coating or finish — so it doesn't fade or wash out over time. The colour shifts depending on the light, which makes it one of the more distinctive short swim trunks in the lineup.
The Liner: Built-In, Barely There
The Modern Trunk uses Bather's exclusive mesh liner — an ultra-fine 90% nylon, 10% spandex construction developed to replace the scratchy, slow-drying liners standard in most swimwear.
The finer weave is what gives it a barely-there feel against the skin, and what lets it dry fast after you're out of the water. Four-way stretch means it moves in every direction without pulling or bunching. No chafing, no clinging, no leaving the beach still soaking. If you've tried swim trunks with a liner before and been disappointed, this is a different construction.
The Pockets
Reinforced angled side pockets with an interior key ring. Back pocket with a zipper closure. The angled cut keeps pockets flat against the body so they don't add bulk to the silhouette. The zipper secures anything you're carrying in the water. The key ring keeps keys off the bottom of the pocket where they'd dig in. All pockets drain quickly with mesh linings
Finding the Right Fit in Short Swim Trunks
The Modern Trunk is built for a sharper silhouette without giving anything up in comfort or performance.
- 4.5-inch inseam — shorter and more tailored than the classic trunk
- Elasticized waistband with internal drawstring that moves with you
- Exclusive mesh liner that's barely there and dries fast
- Recycled nylon and polyester shell built to hold colour and shape
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Available in seersucker or iridescent — two quick-dry fabrics, same precision fit
Match your pant waist to the size chart. Everything else is already taken care of.