Merino Bras and Bikini Bottoms: Fit and Care Questions Answered

Quick answer

Merino underwear fits like a slim, stretchy second layer, not a compression garment. Size by your usual underwear size and use the adjustable hooks on bras to fine-tune support. Wash cold on gentle, skip the dryer, and merino holds its shape without shrinking. The Women's Merino 150 Siren Bikini is a good starting point if you want a soft, durable everyday pair.

How should a merino bra fit?

A merino bra should sit flush against your ribcage without digging in, and the cups should lie smooth rather than gaping or compressing. Because merino has natural stretch and recovery, the band often feels snugger when you first put it on and relaxes slightly with body heat. Start with your usual band size and adjust the hooks to the loosest setting that still stays put. If you are between band sizes, go up rather than down so the fabric can do its job without strain.

What support can I expect from a wool bra?

Merino bras are designed for everyday comfort and light-to-moderate support, not high-impact running. The fabric's stretch and the cut of the bra determine how much lift you get. For travel or long days, that lighter support is usually enough because the bra moves with you and resists odour. If you need more hold, look for a style with a wider band and adjustable straps rather than sizing down, which can cause the fabric to pull and lose shape.

How do I choose the right size in merino bikini bottoms?

Use your hip measurement as the main guide, then check the rise. Merino bikini bottoms are cut to sit close without cutting in, and the fabric will give slightly as you wear it. If your hip measurement falls between two sizes, choose the larger size for a smoother line and less strain on the seams. The Women's Merino 150 Siren Bikini uses a modern slim fit, so if you prefer a looser feel, that is a reason to size up rather than a sign the fit is wrong.

Does merino underwear shrink?

Merino can shrink if you expose it to high heat, so the short answer is: not if you wash it correctly. Cold or lukewarm water on a gentle cycle, then air dry flat or line dry. Heat from a dryer or a hot wash is what causes wool fibres to contract. Follow the care label and your merino underwear will keep its size and shape through many wears.

How do I wash and dry wool underwear?

Turn garments inside out, use a wool-safe or gentle detergent, and avoid fabric softener, which coats the fibres. Machine wash cold on a delicate cycle or hand wash, then press out excess water instead of wringing. Dry flat away from direct sun or heat. For travel, you can rinse merino in a sink and it will dry overnight in most climates, which is why wool underwear works well for carry-on packing.

Is merino underwear good for travel?

Yes, for two practical reasons: odour resistance and quick drying. Merino fibres naturally resist odour, so you can wear a pair longer between washes, and they dry fast after a sink rinse. That means fewer pieces in your bag and less time in a laundry room. Pair a merino bra with one or two bikini bottoms and you have a lightweight underwear system that handles changing climates and long travel days.

Will merino bras and bikini bottoms feel itchy?

Fine merino used in next-to-skin underwear is soft, not scratchy. The Siren Bikini uses corespun fabric that wraps merino around a nylon core, which makes it smoother and more durable than plain wool. If you have sensitive skin, that construction is usually the difference between 'wool is itchy' and 'I forgot I was wearing wool.'

Quick answers to common fit and care questions

How do I know if my merino bra fits?

The band stays put on the loosest hook, cups lie smooth, and you can breathe and move without the fabric pulling. If it digs in or rides up, adjust the hooks before changing size.

Should I size up or down in merino bikini bottoms?

Use your hip measurement. If you are between sizes, go up for a smoother line and less seam strain. The Siren Bikini is a slim fit, so size up if you prefer a little more room.

What is the one care rule that prevents shrinking?

Keep heat away: cold wash, no dryer, air dry flat. Heat is the enemy, not water.

Product facts

• Women's Merino 150 Siren Bikini: Soft and stretchy merino wool underwear with a modern slim fit, the Siren Bikini features corespun fabric that is incredibly soft and durable. The corespun build adds durability and next-to-skin softness, so it works as an everyday or travel pair without feeling fragile.