How do I make a DIY dolphin costume?

Wear a grey hoodie and sweatpants. Cut a white felt oval for the belly and fabric-glue it to the front. Cut a fin shape from grey foam, attach it to the back of the hoodie, and add felt eyes to the hood.

Is a dolphin costume warm enough for cold weather?

Yes, most commercial dolphin costumes are made of thick fleece or plush materials, making them excellent for cold Halloween nights.

What shoes should I wear with a dolphin costume?

Simple grey, white, or blue sneakers work best to match the aquatic color palette without distracting from the costume.

AI-generated example

Dolphin Costume

Make a splash in a comfortable, easy-to-wear aquatic look.

The dolphin costume is a popular choice for ocean lovers, school spirit days, and anyone looking for a comfortable, warm Halloween outfit. Typically styled as a plush grey or blue jumpsuit, this look features a dorsal fin, flippers, and a friendly dolphin-faced hood. It is incredibly easy to put together, making it perfect for last-minute events or chilly outdoor trick-or-treating.

Difficulty: Easy
Time: ~15 min
Budget: $30–60

See yourself as Dolphin →What you need Buy the Dolphin costume

Try it on

See yourself as Dolphin

One clear photo of yourself; we render you in this costume — face untouched, full body, about 20 seconds.

Choose or drop a photo of yourselfJPG · PNG · HEIC

One render, $1. No account needed — if it fails you're not charged. Pricing.

Your photo is sent to Google's Gemini API to make the render and isn't used for training. Renders are AI-generated and labelled.

Want a different costume on this photo, or a whole group in costume? Open the Try-On Studio.

Dolphin costume — Example look · AI-generated

You as Dolphin

Result

What you need for a Dolphin costume

Short on time? Buy it ready-made

Spirit Halloween sells the complete Dolphin costume — one box instead of 4 pieces.

Shop Dolphin at Spirit ↗

Plush dolphin onesie
A grey or blue fleece jumpsuit featuring a white belly panel, a stuffed dorsal fin on the back, and a hood with a dolphin snout.
DIY: Use a grey oversized hoodie and sweatpants, then fabric-glue a white felt oval onto the chest.
Amazon
Dorsal fin
A triangular foam fin attached to the back of the costume to create the classic dolphin silhouette.
DIY: Cut a fin shape out of grey cardboard or foam board and safety-pin it to the back of a grey sweatshirt.
Amazon
Flipper sleeves
Sleeves that taper into flat flipper shapes, often with wrist slits so you can still use your hands.
DIY: Cut flipper shapes out of grey felt and sew or safety-pin them to the cuffs of your sleeves.
Amazon
Grey sneakers
Simple, comfortable canvas shoes or sneakers in grey or white to match the body of the costume.
DIY: Wear any comfortable grey or white shoes you already own.
Amazon

Rather not assemble it? See ready-made Dolphin costumes at Spirit Halloween ↗

How to put it together

1
Put on a lightweight base layer, like a t-shirt and leggings, to stay comfortable inside the plush fleece jumpsuit.
2
Step into the dolphin onesie and zip or button it up to the chest.
3
Pull the hood over your head, adjusting it so the dolphin snout and eyes sit comfortably on your forehead.
4
Slip your hands into the flipper-style sleeves, or pull them back through the wrist slits if you need to hold items.
5
Put on matching grey or white sneakers to complete the seamless aquatic look.

Makeup & hair

Keep your hair tied back in a low ponytail or bun so it fits easily under the onesie hood. If you want a playful touch, apply blue or silver face glitter to your cheekbones.

Dolphin for couples, groups, kids & more

couples: Pair up as a dolphin and a marine trainer, with one person in the dolphin suit and the other in a wetsuit with a whistle.
group: Create a pod of dolphins in different shades of grey and blue, or pair with other marine life like sharks and whales.
kids: A toddler dolphin bunting or a child-sized fleece onesie is warm and adorable for cold Halloween nights.
Plus size: Look for loose-fitting, oversized fleece onesies which offer a comfortable, flexible fit for all body types.
pet: A simple grey dog hoodie with an attached foam dorsal fin on the back.

Tips

Fleece onesies can get very warm, so wear breathable cotton layers underneath to prevent overheating.
If your onesie covers your hands with flippers, make sure they have wrist slits so you can easily use your phone or hold a drink.
Keep the plush fabric clean by spot-cleaning with a damp cloth instead of machine washing right before your event.

Dolphin costume FAQ

How do I make a DIY dolphin costume?: Wear a grey hoodie and sweatpants. Cut a white felt oval for the belly and fabric-glue it to the front. Cut a fin shape from grey foam, attach it to the back of the hoodie, and add felt eyes to the hood.
Is a dolphin costume warm enough for cold weather?: Yes, most commercial dolphin costumes are made of thick fleece or plush materials, making them excellent for cold Halloween nights.
What shoes should I wear with a dolphin costume?: Simple grey, white, or blue sneakers work best to match the aquatic color palette without distracting from the costume.

Did you know? Dolphins are known for their high intelligence and social behavior, often living in tight-knit family groups called pods.