How do you make a DIY killer whale dorsal fin?

Cut a curved triangle out of sturdy cardboard, cover it with black felt or paint, and secure it to the back of a black hoodie using heavy-duty safety pins or hot glue.

What is the easiest way to dress up as an orca?

The easiest method is purchasing a pre-made plush orca onesie, which includes the hood, dorsal fin, and tail flukes in one piece.

Where do the white patches go on an orca costume?

The large white patch goes on the front belly, and two distinct white oval patches go on the sides of the head, just behind and above the eyes.

AI-generated example

Killer Whale Costume

Make a splash in a classic black-and-white ocean predator look.

The killer whale, or orca, is one of the ocean's most recognizable and striking marine mammals. A popular choice for school plays, Halloween, and group themes, this costume relies on a bold black-and-white color scheme. The look is typically achieved using a plush zippered onesie or a DIY black hoodie modified with felt patches and a cardboard dorsal fin.

Difficulty: Easy
Time: ~30 min
Budget: $25–60

See yourself as Killer Whale →What you need Buy the Killer Whale costume

Try it on

See yourself as Killer Whale

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

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

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

Killer Whale costume — Example look · AI-generated

You as Killer Whale

Result

What you need for a Killer Whale costume

Short on time? Buy it ready-made

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

Shop Killer Whale at Spirit ↗

Black hooded sweatshirt or onesie
A solid black zip-up hoodie or a full-body plush fleece onesie serves as the base of the costume.
DIY: Use an old black oversized zip-up sweatshirt.
Amazon
White felt fabric
A large sheet of white felt or fabric to create the signature white belly and eye patches.
DIY: Cut up an old white t-shirt.
Amazon
Black craft foam or cardboard
Stiff material used to construct the upright dorsal fin on the back.
DIY: Use shipping cardboard painted black.
Amazon
Black pants or joggers
Matching black pants to complete the lower half if using a hoodie instead of a onesie.
DIY: Any plain black sweatpants or leggings from your closet.
Amazon

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

How to put it together

1
Put on the black base layer, such as a black zip-up hoodie and matching black pants, or a plush orca onesie.
2
Cut a large oval shape from the white felt to represent the whale's underbelly and fabric-glue or safety-pin it to the front of the torso.
3
Cut two elongated white oval patches from felt and attach them to the sides of the hood, just above where your eyes sit, to mimic the orca's eye patches.
4
Cut a large triangular dorsal fin shape out of sturdy cardboard or black craft foam.
5
Cover the cardboard fin in black felt or paint it black, then attach it securely to the upper back of the hoodie using safety pins or fabric glue.
6
Wear black shoes or sneakers to maintain the seamless dark look of the lower body.

Makeup & hair

Keep hair tucked completely inside the hood. If desired, apply simple black and white face paint around the eyes to blend in with the hood's design.

Killer Whale for couples, groups, kids & more

couples: Pair with a marine biologist, trainer, or another ocean animal like a shark.
group: Create a 'pod' of killer whales with friends, or a full ocean life group with sharks, seals, and penguins.
kids: Use a black toddler zip-up hoodie with felt pieces glued on for an easy, warm trick-or-treating outfit.
Plus size: A loose-fitting plush fleece onesie offers a comfortable, flexible fit for all body types.
pet: A simple black dog vest with a small foam dorsal fin attached to the back.

Tips

If making a DIY dorsal fin, use lightweight foam instead of heavy cardboard so it doesn't drag the back of your hoodie down.
Onesies are highly comfortable and warm, making them perfect for chilly outdoor Halloween nights.
Ensure the white belly patch is securely fastened with safety pins if you plan to wash the hoodie later.

Killer Whale costume FAQ

How do you make a DIY killer whale dorsal fin?: Cut a curved triangle out of sturdy cardboard, cover it with black felt or paint, and secure it to the back of a black hoodie using heavy-duty safety pins or hot glue.
What is the easiest way to dress up as an orca?: The easiest method is purchasing a pre-made plush orca onesie, which includes the hood, dorsal fin, and tail flukes in one piece.
Where do the white patches go on an orca costume?: The large white patch goes on the front belly, and two distinct white oval patches go on the sides of the head, just behind and above the eyes.

Did you know? Orcas are actually the largest members of the dolphin family, not true whales.