Fish Onesie

£39.99

  • Made from: flannel, for optimal warmth and comfort
  • Design: stylized fin patterns for an aquatic touch, fin on the hood
  • Fit: roomy, offering complete freedom of movement
  • Occasions: pool parties, Halloween, aquarium trips, cosy nights in
  • Care: machine washable, keeps its softness wash after wash
  • Ultra-soft fabric | Warm and comfortable
  • Pyjamas and costume | Two in one
  • Any occasion | Bedtime, parties, film nights
  • Gift-ready | One they’ll actually wear
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Size Chart

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Fish Onesie

Fish Onesie

£39.99

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  • Made from: flannel, for optimal warmth and comfort
  • Design: stylized fin patterns for an aquatic touch, fin on the hood
  • Fit: roomy, offering complete freedom of movement
  • Occasions: pool parties, Halloween, aquarium trips, cosy nights in
  • Care: machine washable, keeps its softness wash after wash

Women’s Fish Onesie lets you swim through gentle freshwater depths in total comfort

Discover the fish onesie for adults, a one-piece pyjama set designed to turn your evenings into true moments of relaxation. As soon as you slip it on, you dive into a soothing universe inspired by the elegance of marine creatures. Its design recalls the lightness of water and the fluid motion of fins. Every detail evokes the calm of the depths, the silent ripple of a fish gliding between the corals.

The flannel texture is soft and comforting. It keeps the warmth in without stifling, ideal for long evenings at home. The patterns bring a touch of whimsy, while the roomy fit ensures total freedom of movement, as if you were swimming in your own aquarium.

A true marine creature of the deep in a Men’s Fish Onesie

This adult fish onesie is much more than just nightwear. It blends aquatic whimsy with absolute comfort to create an outfit that is both original and wonderfully pleasant to wear. Its plush hood, decorated in an aquatic spirit, adds a playful touch. Perfect for keeping your head nice and warm on cool evenings.

The elastic long sleeves offer a gentle fit without squeezing. They keep the cold air from creeping in and follow your movements without constraint. Order your one-piece now and get ready to sail towards the softest, most stylish dreams.

Explore more aquatic styles.

For a first family photo in matching outfits, the baby fish onesie offers this look in a baby size. Bigger fish swim in the blue shark onesie. Explore the animal onesies collection to discover the rest of the menagerie.

Frequently Asked Questions

They’re made to keep you warm on the sofa through autumn and winter, so yes, they’re cosy. The relaxed fit lets air move around, though, so you won’t get that stuffy feeling you get from tight pyjamas.
Machine wash at 30°C on a gentle cycle. Turn them inside out and pop them in a mesh laundry bag to protect the hood. Skip the tumble dryer and the iron. They air-dry quickly and fluff right back up on their own.
Yes, every onesie we sell is unisex. The roomy cut works for men and women alike, our kids’ styles fit girls and boys just the same, and our baby sizes are cut the same way for everyone. Just check the size chart to find your fit.
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Adult size chart (measurements in cm)

SIZEHEIGHTCHESTSHOULDER WIDTHSLEEVE LENGTHONESIE LENGTH (EXCLUDING HOOD)
S144 - 1531164650127 - 130
M154 - 1631204853137 - 140
L164 - 1731245056147 - 150
XL174 - 1831285259157 - 160