Bikini top - Sidsel
Loved by +25,000 women
Who is it named after?
Who is it named after?
Material
Material
Washing guide
Washing guide
How does it work?
How does it work?period swimwear is like flow period underwear sewn with a built-in bandage, consisting of a minimum of 3 technical layers, which directs liquid down into the bandage, absorbs the liquid and ensures that you do not bleed or drip through.
👉 You can read much more about how period swimwear works in the guide here.
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Flow's founder
Relaunch of Period Swimwear 2026
"In 2024, we launched period swimwear for the first time with Cartel, and it was a huge success.
In a month and a half we had sold out, and even though we were able to get a small extra batch, it wasn't enough to meet demand.
Now menstrual swimwear is returning to us - all under our own name, and we have spent two years nerding out fit, materials (we have chosen the best Italian fabrics) - and I have tested function and fit.
I'm not a water dog, but of course the samples I had packed in my suitcase had to stand their test.
They passed the UG. I felt safe, comfortable - and delicious. I am incredibly looking forward to seeing you in your swimsuits on the beach, by the pool, in the gardens."
- Catherine
Want to know more about our menstrual swimwear?
Frequently asked questions
Feel free to take your regular size in your swimwear.
If you are between two sizes, we would suggest the smaller one, as the fabric can give when it is wet.
The suction power i period swimwear is mild to moderate.
If you bleed profusely, we would suggest that you combine with a cup or a disc.
Our swimwear is designed with a built-in absorbent layer that traps and encapsulates menstrual blood. This layer is combined with a waterproof but breathable membrane that prevents you from bleeding through while swimming or sunbathing.
The textiles are light and quick-drying, which ensures that you can move freely and feel dry shortly after being in the water.
1. If you have bled in your menstrual swimwear, rinse them in cold water until it runs clear.
2. Protect your swimwear in a laundry bag and wash your panties with similar colors at 30-40 degrees.
Tip: You can wash with our Allergy Certified special detergent Bloody Clean .
3. Dry them inside out on a clothesline - and you're good to go again.
👉 Read our full guide on how to take good care of your swimwear here.
Travel-size laundry detergent?
Bikini top - Side-tie with wide straps and square neckline
Bikini top Sidsel is an elegant bikini top with wide straps and a modern square neckline that gives a clean, timeless and flattering look. It is designed for those who want a bikini top with comfortable support and a secure fit - whether you are swimming, sunbathing or moving around.
The top is made of exclusive Italian ECONYL® with 4-way stretch, which molds to the body and provides a soft, flexible fit all day long.
Bikini top - Sidsel is a comfortable bikini top with support without underwire
The Sidsel bikini top is developed with a focus on natural support rather than underwire.
The wide straps distribute the weight comfortably across the shoulders, while the discreet elastic under the bust helps the top stay in place. The lined front provides extra support and a nice drape, so you can feel comfortable – both in and out of the water.
The modern square neckline highlights the collarbone and shoulders and gives the top an elegant, Scandinavian look.
Italian quality with high comfort
The Sidsel bikini top is sewn in exclusive Italian ECONYL®, a durable material with 4-way stretch that provides high freedom of movement and a comfortable fit.
The material dries quickly, keeps its shape and is designed for many hours of use at the beach, pool or on vacation.
Designed to match our period bikini
The Sidsel bikini top is designed as the perfect match for period bikini - Sidsel bikini bottom, but can also be combined with the other bikini briefs in our collection of period swimwear.
Mix and match models and colors to get a bikini set that suits both your style and your needs.
Our menstrual bikini briefs protect against light to moderate period and can be combined with a menstrual cup or menstrual disc for extra security in case of heavier bleeding.
That's why many people choose the Sidsel bikini top
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Bikini top with wide straps for comfortable support
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Elegant square neckline
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Lined front for extra hold
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Discreet elastic under the bust
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Quick-drying material with 4-way stretch
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Matches period bikini - Sidsel bikini bottom
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Part of Flow's collection of period swimwear
Frequently asked questions
Does Sidsel Top provide good support?
Yes. Sidsel Top is designed with wide straps, a discreet elastic under the bust and a lined front, which together provide comfortable and natural support without underwire.
Does the top have underwire or inserts?
No. Sidsel Top is non-wired and designed with a focus on comfort and a natural fit.
What material is the top made of?
The top is made of exclusive Italian fabric with 4-way stretch. The material dries quickly, keeps its shape and provides high freedom of movement.
Can I combine the top with other bikini bottoms?
Yes. The Sidsel bikini top is designed to match the Sidsel bikini bottoms, but can also be mixed with the other bikini bottoms in Flow's collection of period swimwear.
Can the top be used without period?
Yes. The Sidsel bikini top is a regular bikini top and can be worn all summer long – no matter where you are in your cycle.
Who is the model suitable for?
The Sidsel bikini top is a great choice if you prefer a bikini top with a little more coverage, wide straps and a supportive fit.
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