Underwear, rethought

One garment.
Every body.
Every day.

Breathable boxer shorts with a detachable pad liner for periods. Quick-dry fabric that doubles as swim trunks. Built for everyone.

See the Product

$1.1B

Period underwear market by 2036

0

Competitors doing swim + period

17%

Annual market growth rate

Period underwear shouldn't mean giving up your style

1

Built-in absorbency traps heat

Sewn-in layers don't breathe. They hold moisture, take forever to dry, and create the exact environment bacteria love.

2

Feminine-coded or overpriced

Current options are either lacy boyshorts at $40/pair or "gender-neutral" boxers that still only come in women's sizing.

3

Single-purpose garments

You buy period underwear for 5 days a month. The rest of the time, they sit in a drawer. What if they worked at the beach too?

The FlowTrunks difference

Detachable protection. Quick-dry fabric. Zero compromise.

01 Core Innovation

Snap-in Pad Liner

Breathable, organic cotton gusset with secure attachment points. Snap the pad in during your period, remove it when you don't need it. Wash separately. No PFAS chemicals.

02 Dual Purpose

Swim-Ready Fabric

Quick-dry, chlorine-resistant material that performs in water. Wear them to the pool, the beach, or just around the house. One garment, no limits.

03 For Everyone

Actually Unisex

Not "women's boxers" with a masculine label. Truly designed for every body. Periods, swim, everyday wear. Same garment, different use cases.

What exists vs. what should

Current Options

  • Built-in absorbent layers that trap heat
  • $30-50 per pair, period-only use
  • Women's sizing labeled "inclusive"
  • Can't get wet, can't swim in them
  • PFAS concerns in absorbent layers
vs

FlowTrunks

  • Detachable pad keeps the garment breathable
  • $20-28 per pair, everyday + swim use
  • True unisex fit with universal sizing
  • Quick-dry, swim-ready out of the box
  • Removable liner means zero chemical contact

The garment that goes where you go

From the bedroom to the boardwalk. From your period to the pool. One pair of FlowTrunks replaces the drawer full of single-purpose underwear you never feel great about wearing.

Configure Your Pair →
Wear everything. Worry about nothing.