How to Make a Shark Fin Costume

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If you're like most people, one of the first things that springs to mind when you think of a shark is its most iconic feature: the dorsal fin. Any good shark costume will be incomplete without a fin, and you might even wear the fin on its own in certain circumstances, such as when singing "Baby Shark" at a child's shark-themed birthday party or watching shark week on TV. You may also want to wear a fin-shaped headband just for fun.


A shark fin is a basic shape, and making one that's attachable is relatively simple, but it's important to take care to make the fin fit comfortably and look believable. In this tutorial, learn how to make a last-minute shark fin to enhance your costume ideas, party ideas and dress-up fun with just a few simple supplies from your local craft store or Amazon.


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Things You'll Need

  • Graph paper or newsprint

  • Scissors

  • Straight pins

  • Foam rubber

  • Craft knife

  • 2 cloth belts

  • Safety pins

  • Needle and thread or sewing machine

  • Dark gray spray paint

Make The Fin

1. Create the shark fin template

Draft a paper fin pattern on graph paper or newsprint. Start with a large sketch of a right triangle and then reshape the short side to have a dramatic inward curve. Give a slight outward curve to the outside acute angle as well. Cut out the pattern with scissors. Make sure the shark fin template is the exact size and shape you want before moving on to the next step.


2. Cut out the foam shark fin

Cut the pattern from foam rubber. Pin the pattern to the foam rubber using straight pins and then cut the rubber around the outside of the pattern using a craft knife. If your foam shark fin shape is slightly off, use the craft knife to trim it up a bit until the shark fin is to your liking.


Attach the Straps

1. Fasten straps for your shark fin costume

Fasten two belts to your torso. One belt should be at the broadest point of your chest if you're a man or beneath your breasts if you're a woman. The other belt should be placed across your hips. Make sure both belts are snug but comfortable.



2. Pin the belts to your DIY shark fin

Temporarily pin the fin to the belts. Position the fin where you want it and then use safety pins to attach the fins where they meet up with the belts. You may need the help of a friend, or you can turn the belts around on your own body and pin the fin in front of you. Check a full-length mirror to make sure the fin is where you want it to be.


3. Sew the belts to your Halloween costume

Permanently attach the fin to the belts. Remove the belts from your body and then sew the fins to the belts where they're attached by the safety pins either by hand or by using a sewing machine. Sew along the edge of the foam rubber using a whip stitch (over and around).


Paint your shark fin costume

Spray paint the fin. If your fin needs extra stiffness, you can use extra layers of paint to achieve that result. Just be sure to allow your fin to dry thoroughly before wearing it.


Shark fin costumes are simple to make, and they can be worn for a variety of reasons, including playing dress-up and for a Halloween costume. You can even have kids join in on the fun and help you create a shark fin costume of their own.



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