Size & Fit Guide
Finding the right fit should feel as effortless as the pieces themselves.
Proto Marín silhouettes are designed to flatter naturally — supportive where you want structure, relaxed where you want movement — without compromising comfort.
Use the guide below to help choose your best size. If you’re between sizes, we generally recommend sizing up for comfort.
How to Measure
Use a soft measuring tape and measure over lightweight clothing.
Bust
Measure around the fullest part of your bust, keeping the tape parallel to the floor.
Underbust
Measure directly under the bust — this helps determine support and band fit.
Waist
Measure at the narrowest part of your waist, just above the belly button.
Hip
Measure around the fullest part of your hips and seat.
Tip: Stand naturally and don’t pull the tape too tight — your pieces should move with you.
Size Chart
| Size |
| Bust XS |
| Underbust XS |
| Waist XS |
| Hip XS |
| Size | XS | S | M | L |
|---|---|---|---|---|
| Bust | 32-33.5 | 33.5-35 | 35-37 | 37-39 |
| Underbust | 26-28 | 28-29 | 29-31 | 31-33 |
| Waist | 25-26 | 26-28 | 28-30 | 30-32 |
| Hip | 35-36.5 | 36.5-38 | 38-40 | 40-42 |
* Sizes are American and expressed in inches.
International Size Chart
| Size |
| US XS |
| AU / UK XS |
| Cup XS |
| Size | XS | S | M | L |
|---|---|---|---|---|
| US | 0-2 | 2-4 | 4-6 | 6-8 |
| AU / UK | 4-6 | 6-8 | 8-12 | 12-14 |
| Cup | A-B | B-C | B-C | C-D |
Fit Notes by Style
Because each silhouette is intentionally designed, fit may vary slightly.
One-Pieces
Sculpting and supportive through the midsection.
If you have a longer torso, consider sizing up.
Bikinis — Tops
Designed to feel secure without digging.
For fuller busts, choose your regular size for support or size up for softer coverage.
Bikinis — Bottoms
Mid-rise to high-hip shapes that elongate the leg.
If you want more coverage at the back, size up.
Fabric & Stretch
Our fabrics are chosen for:
- soft hand feel
- gentle sculpting
- recovery that holds shape over time
Because of the natural stretch, your suit may feel snug on first wear — it will soften slightly and mold to your body.
Still Unsure?
We’re happy to help.
If you’d like personalized sizing guidance, send us:
✔ your bust, waist, and hip measurements
✔ the style you’re considering
✔ the type of fit you prefer (supportive, relaxed, cheeky, more coverage)
We’ll recommend the best size for you.