How To Find The Right Fit: The Active Trunk
The Active Trunk is built for more than the beach. A 3.5-inch inseam, DotAir® mesh shell, and compression liner with a built-in phone pocket make it the shortest and most performance-oriented trunk in the Bather lineup. A hybrid swim short that works in the pool, at the gym, on a run, and everywhere after.
Start With The Waist
The Active Trunk uses an elasticized waistband with an internal drawstring. Match the waist of your favourite pair of jeans to the chart below. The drawstring and stretch waistband give you flexibility if you sit between sizes. The Active Trunk runs from XXS to XXXL, extending the size range beyond the Classic Swim Trunk and Modern Trunk.
*All measurements in inches
| Size | XXS | XS | S | M | L | XL | XXL | XXXL |
|---|---|---|---|---|---|---|---|---|
| Pant Size | 26-27 | 28-29 | 30-31 | 32-33 | 34-35 | 36-37 | 38-39 | 40-41 |
| Waist | 13.5 | 14.5 | 15.5 | 16 | 17 | 18 | 19 | 20 |
| Inseam | 3.5 | 3.5 | 3.5 | 3.5 | 3.5 | 3.5 | 3.5 | 3.5 |
The Inseam: Why 3.5 Inches
At 3.5 inches, the Active Trunk is Bather's shortest trunk yet, sitting a full inch shorter than the Modern and two inches shorter than the Classic. The inspiration was vintage running shorts that sit high on the thigh and move without restriction. The 90s track silhouette was reengineered for the water, reducing drag and eliminating bunching across every kind of movement.
The Fabric: DotAir®
The Active Trunk shell is made from 100% recycled Japanese DotAir® nylon, a 91 GSM open-mesh fabric engineered for maximum airflow. The dot-pattern weave creates thousands of micro-vents across the surface, pulling air through the fabric rather than trapping heat against the skin. A performance fabric that maximizes breathability, it's also quick-drying, and lightweight.
The Liner: Compression
Perfecting the Swim Trunk liner is what Bather knows best, and the Active Trunk is an exciting evolution. Our first trunk with a compression liner, the Active Trunk is engineered to keep everything in place through high-intensity movement. No shifting, no adjusting mid-run, no reason to wear a separate layer underneath. It's what makes the Active Trunk function as a genuine hybrid swim-to-everything short.
If you're looking for our signature barely there mesh liner, shop our Classic and Modern swim trunks.
The Pockets
The tradeoff with a short, lightweight shell is that there's nowhere to put anything without weighing it down. The solution was to move the phone pocket off the shell entirely. It lives in the compression liner instead, flat against the thigh, where it doesn't pull on the fabric or disrupt the silhouette. Your phone stays put during movement without the shell ever knowing it's there.
On the outside: a zippered back pocket with reinforced stitching for cards or keys, that drains quickly after swimming.
Finding The Right Fit In The Active Trunk
The Active Trunk is the performance end of the Bather lineup with the shortest inseam, lightest fabric, and only compression liner.
- 3.5-inch inseam — 90s inspired, built for movement
- DotAir® shell made from 100% recycled Japanese nylon engineered for airflow
- Compression liner that holds the body, moves in four directions, dries fast
- Built-in phone pocket secured against the thigh in the liner
- XXS to XXXL — the widest size range in the lineup
Match your jeans waist to the chart. Everything else is already handled.
Shop The Active Trunk