One Piece n°4 - Blue Lagoon

$74.00 USD $120.00


The plunging neckline of the range.

The cut

  • A sublime neckline! Plunging but not too much.
  • A belt provides some support for larger cup sizes.
  • Straps adjustable by a system of Italian knots. They can be tied in different ways: straight, crossed in the back or behind the neck.
  • No iron or plastic (avoid micro waste) to adjust the straps but knots. The bows are small in size and comfortable to wear. On the adjustment side, the iron eyelets slide very badly on jersey materials and tend to loosen the straps too quickly; on the contrary, the knots do not loosen when you are in motion.
  • The jersey is lined with our very soft material (and the same color as the main fabric, that's new too!)

All our models have been tested by excellent swimmers and water sports enthusiasts in the south of France. With this one, you will be comfortable for swimming and spending a quiet or festive day at the sea.

Size advice
To choose your one-piece size, refer to your bottom size. For example if you take 36 in panties, take S in one piece. The straps are wide adjustable and will adapt to your top.
This jersey fits normally. If you measure more than 1m70 and you hesitate between two sizes, take the size above.

In case of doubts or questions about the size, do not hesitate to write to us at

Our models
Carmen is 1.80m tall, has an A cup and wears an S (36 below)
Laetitia is 1m76 tall, has a B cup and wears an S (36 below)
Emmanuelle is 1m75 tall, has a C cup and wears an S (36 below)
Sigrid is 1m65 tall, has a D cup and wears an M (see 4.0 red sheet)

Fabric & Care

Posidonia's objective is to use a fabric that contributes to cleaning the oceans and the environment, but also very elegant and comfortable to free women from any constraint of movement. An eco-responsible jersey is also a sustainable jersey, which is why I have chosen the highest range of European fabric made up of waste such as fishing nets and plastic bottles.

78% Recycled Polyamide. 22% Elastane.
Weight: 190gr.
UPF 50 (sun protection).
Bi-directional stretch (marries muscles & movements: great sensation)
Label: OEKO-TEX Standard 100.
Italian fabrics.

🌞 UV protection SPF50


The sea and the salt do not alter your swimsuits if you rinse them with fresh water after each use. Let it dry flat or laid out on its own.

Hand wash your swimsuit. You can wash it in the washing machine at the end of your vacation, on a delicate cycle (max. 30 degrees), with a non-detergent detergent, without spinning or drying cycle.

The chlorine resistance index of our materials is very good. The colors, however, are more delicate.

Customer Reviews

Based on 13 reviews
Pauline Valade

Une Pièce 4.0 - Bleu Lagon

Alexia Arcas
Parfait !

Mon maillot de bain préféré ! Élégant, eco-responsable, de bonne qualité que demander de plus! N’hésitez pas si vous avez un coup de cœur ♥️

Cécilia Brancheriau
Très beau maillot

Couleur qui sort de l'ordinaire, beau maintien de la poitrine. Matière agréable. Taille correctement. Une belle découverte !

Emilie Casteran

Une Pièce 4.0 - Bleu Lagon

Beautiful swimsuit, but not suitable for long torsos

This is an amazing piece of clothing made of high quality materials. It makes me very sad that the model is not particularly suitable for long torsos and is therefore much too short for me.