Sizing Card

Siren's Boutique Sizing Card

Every order ships with a printed sizing card showing measurements across four size systems. This is the same chart, online for reference before you order.

Bikini sizing (top + bottom)

Size AU / UK US EU Bust (cm) Waist (cm) Hip (cm)
XS 6 2 34 78–82 60–64 86–90
S 8 4 36 82–86 64–68 90–94
M 10 6 38 86–90 68–72 94–98
L 12 8 40 90–94 72–76 98–102
XL 14 10 42 94–98 76–80 104–108
XXL 16 12 44 100–104 82–86 110–114
3XL 18 14 46 106–110 88–92 116–120

One-piece sizing

Same bust/waist/hip ranges as above. For one-pieces, also check torso length — measured from the shoulder, over the bust, through the crotch, and back up to the same shoulder. If your torso measurement is over 165 cm, size up one for a comfortable fit.

How to measure

  • Bust: Around the fullest part, parallel to the floor.
  • Waist: The narrowest point, usually about 2.5cm above your belly button.
  • Hip: Around the fullest part of the hips and bottom.

Between sizes?

Size up. Our fabrics have high recovery — they hold shape over 100+ wash cycles, so a slightly looser fit settles in beautifully and stays comfortable.

Returns

Free size-swap returns within 30 days on unworn pieces (hygiene seal intact). See our refund policy for details.

Questions?

Reach us at boutiquesirens@gmail.com or DM @sirens.boutique on Instagram. Founder-led customer service for the first thousand orders.

Engineered for sun, sea, and sand.