Rated 4.7 excellent | 921 reviews
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Rated 4.7 excellent | 921 reviews
All U.S. orders include free shipping with tracking. Orders are processed within 1–3 business days and delivered within 5–10 business days.
Received a damaged or defective item? We've got you covered. Contact us within 30 days of delivery and we'll send you a replacement at no extra cost — no questions asked.
At Oaklyn Wear, every product is carefully selected for quality, comfort, and style. We're a small brand that genuinely cares about every customer's experience — if something isn't right, we'll always make it right. Your satisfaction is everything to us.
Deep V. Open Back. Effortlessly Confident.
Sienna is the one-piece that takes you from beach to evening without skipping a beat. The sleek knit fabric hugs your body with a natural, comfortable stretch, the open back creates a striking, confident silhouette that makes a statement without trying too hard, and the deep V-neckline frames your neckline with a refined elegance that works equally well layered over a bikini or worn completely on its own.

Backless Design That Makes an Entrance The open back is the defining detail that sets Sienna apart — bold enough to turn heads, refined enough to wear anywhere. A confident, striking feature that photographs beautifully from every angle.
Deep V-Neckline That Flatters The clean V-neckline elongates your torso and draws the eye with a sophisticated, relaxed confidence — balanced beautifully by the open back for a look that feels considered rather than overdone.
Knit Fabric That Moves With You The natural stretch of the knit construction follows your body's movement without restriction — close-fitting and body-skimming while remaining genuinely comfortable through long warm-weather days and evenings out.
Bodycon Silhouette That Works Two Ways Layer over a bikini for beach days or wear on its own for evening outings — Sienna transitions between both effortlessly without losing any of its impact.
Order Sienna today before your size sells out.

SIZE CHART
Estimated sizing based on standard progression — when between sizes size up.
| Size | Top Length (in) | Chest Half Circ. (in) | Pant Length (in) | Pant Width Half (in) | Pant Leg Opening (in) | Waist Half Circ. (in) |
|---|---|---|---|---|---|---|
| XS | 16.1" | 11.4" | 39.0" | 9.1" | 8.3" | 7.5" |
| S | 16.5" | 12.2" | 39.8" | 9.8" | 9.1" | 7.9" |
| M | 16.9" | 13.0" | 40.6" | 10.6" | 9.8" | 8.3" |
| L | 17.3" | 13.8" | 41.3" | 11.4" | 10.6" | 8.7" |
| XL | 17.7" | 14.6" | 42.1" | 12.2" | 11.4" | 9.1" |
| XXL | 18.1" | 15.4" | 42.9" | 13.0" | 12.2" | 9.4" |
| XXXL | 18.5" | 16.1" | 43.7" | 13.8" | 13.0" | 9.8" |
Care Instructions: Hand wash cold, lay flat to dry to preserve shape and stretch.
⚠️ Note: XS, XXL, and XXXL measurements are estimated based on standard sizing progression from supplier data. Flat lay measurement — an error of 1-3cm is normal. If you have exact supplier measurements for these sizes please replace with those for accuracy.
When in doubt, size up for extra comfort and a perfect fit.