Sea Animal Costume
Make a splash with creative, easy-to-build ocean creature costumes.
Sea animal costumes are a fantastic, versatile choice for Halloween, school plays, and ocean-themed parties. Whether you want to transform into a glowing jellyfish, a fierce shark, or a deep-sea diver, these looks are highly customizable and fun for all ages. This guide focuses on the popular, crowd-pleasing DIY jellyfish and classic sea creature styles that you can easily assemble at home.
- Difficulty
- Easy
- Time
- ~45 min
- Budget
- $15–50
Try it on
See yourself as Sea Animal
One clear photo of yourself; we render you in this costume — face untouched, full body, about 20 seconds.
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.
What you need for a Sea Animal costume
Short on time? Buy it ready-made
Spirit Halloween sells the complete Sea Animal costume — one box instead of 5 pieces.
Clear dome umbrella
A classic bubble umbrella to serve as the main bell of the jellyfish.
DIY: Use a wide-brimmed straw hat wrapped in blue or white fabric.
Ribbons and yarn
An assortment of iridescent, white, pink, and blue ribbons, lace, and yarn to act as tentacles.
DIY: Cut strips of bubble wrap, plastic tablecloths, or old t-shirts.
Battery-operated LED fairy lights
A string of cool white or blue micro LED lights to tape inside the umbrella dome.
Monochromatic base layer
A matching long-sleeve shirt and leggings or pants in white, light blue, or lavender.
DIY: Use any matching solid-colored sweatpants and sweatshirt from your closet.
Felt sea creature mask
A simple felt mask depicting a fish, crab, or sea turtle for quick character identification.
DIY: Cut a simple fish or starfish shape out of colorful craft felt and attach an elastic band.
Rather not assemble it? See ready-made Sea Animal costumes at Spirit Halloween ↗
How to put it together
- 1
Put on your solid-colored base layer (white, blue, or purple works best for an underwater vibe).
- 2
Open the clear dome umbrella and use clear packing tape to secure the battery pack of the LED fairy lights to the center handle.
- 3
Weave and tape the LED light strings along the inside metal ribs of the umbrella to illuminate the dome.
- 4
Tie or tape long strands of iridescent ribbons, yarn, and lace along the outer edge of the umbrella so they hang down like tentacles.
- 5
Put on your felt mask or sea-themed headband to complete the aquatic creature aesthetic.
- 6
Hold the illuminated umbrella over your head to instantly transform into a glowing jellyfish.
Makeup & hair
Keep hair sleek and pulled back in a ponytail or bun to stay out of the way of the hanging tentacles. Apply blue, silver, or iridescent glitter makeup to your cheekbones for a shimmering, wet-look ocean glow.
Sea Animal for couples, groups, kids & more
- couples
- One person goes as a glowing jellyfish, and the other dresses as a scuba diver with a black outfit, goggles, and a painted soda-bottle oxygen tank.
- group
- Create an entire school of sea life, including sharks, crabs, lobsters, starfish, and jellyfish using matching felt masks and color-coordinated outfits.
- kids
- A simple shark fin backpack or a colorful felt fish mask paired with a matching hoodie makes a comfortable, warm, and adorable option.
- Plus size
- A loose-fitting, oversized blue or teal poncho decorated with felt seaweed and fish cutouts offers a comfortable, flowing, and highly customizable fit.
- pet
- A lightweight shark fin harness or a soft lobster-shaped costume that straps comfortably around your dog's chest.
Tips
- If carrying an umbrella all night is too tiring, attach the ribbons and lights directly to a wide-brimmed hat instead.
- Keep safety in mind: make sure your hanging tentacles are cut to a length that won't trip you while walking.
- For outdoor nighttime events, the LED lights are a great safety feature that keeps you highly visible to traffic.
- Opt for battery packs with a simple on/off switch that you can easily reach while holding the umbrella.
Sea Animal costume FAQ
- How do I make a cheap DIY jellyfish costume?
- Use a clear bubble umbrella, tape battery-powered fairy lights inside, and hang strips of bubble wrap, plastic tablecloths, and cheap ribbon from the edges. Wear matching solid-colored clothes underneath.
- What are some easy sea animal costumes for groups?
- A 'Under the Sea' theme is perfect for groups. You can use simple felt masks or headbands representing sharks, crabs, octopuses, and starfish paired with color-matching sweatsuits.
- How do you make a scuba diver oxygen tank?
- Paint two 2-liter soda bottles silver or bright yellow, tape them together, attach a black plastic tube as the regulator hose, and hot glue elastic bands to wear it like a backpack.
Did you know? There are over 240,000 documented marine species in our oceans, meaning there is virtually no limit to the unique creatures you can use as inspiration for your next costume.