This Halloween my big project was making a mermaid costume, or technically Amphitrite, Goddess of Sea. Everything I used to put it together was from Amazon or Shein, and then I reworked those pieces to make them better.

In this post I’ll break down the costume pieces, hair and make-up so you can recreate the parts you like to make your own mermaid or sea siren. Short on time? Click here to see everything tagged on Amazon.

The Mermaid Costume Pieces: Top, Corset, Tail

Starting from top to bottom:

The sparkly blue and green top is from Shein. I removed the straps and the rhinestone trim. The top was a little floppy without the straps, so I reenforced the inside with Worbla to make it hold the shape I wanted. You won’t need to do that if you just leave the straps attached. *Click here to shop on Shein and save 10%

The mermaid corset started as an old corset I already had. Then I covered it in basketweave upholstery fabric and changed the color to a blue green. I started with a leather dye spray, and then decided I wanted it to be more shimmery, so I went over it with an iridescent acrylic paint. Click here for the Embossed Faux Leather fabric I used, shown below.

Here’s a reel of me making the corset and wearing the first version of the costume. In the next paragraph, you’ll see I ended up changing the skirt. I had a bit of a different direction with the first one, and was going for a mermaid who was caught up in a pirate’s net and now lives on land. So I had a layered flowing skirt, netting and seaweed wrapped around me. For Amphitrite, I made the bottom more mermaid tail-like. (Just click the box if it is not displaying. The blog has been being a bit weird this morning)

Mermaid Tail Skirt

The mermaid skirt was purchased on Amazon (click here for skirt), and then I added extra fabric to the bottom tail part, and side fins at the top. The skirt seemed to run a bit large, so I had to take it in to fit tightly and then flare out. I would suggest ordering your size- I ordered a size up because I’m always worried things will be too small and it’s easier to take them in. And I was ordering without enough time to do an exchange. I loved the skirt as-is, but always have to add a little something extra so I sewed more fabric around the bottom in blue and purple.

Mermaid Accessories: Tiara, Fins and Trident

The Mermaid Tiara

I got the tiara and squid tentacles on Shein, then added my own jewels and shells. The tentacles were actually hair clips, so I removed the clips and glued them together to make the top of the crown. The reel posted above actually shows a bit of making the tiara, when I’m gluing the tentacles together.

Siren Ear and Wrist Fins

I added ear fins and wrist fins. These pieces started out as a kid’s mermaid costume. (Click here to find it on Amazon.) The ear fins are great as-is, but I painted them to match my costume and added a bit of fabric to the back.

The tail piece is kind of silly. It’s this short toddler-size foam tail that you are supposed to clip to your waist. But what I really wanted it for was the tail fins. I took those off, painted them, and then attached them to wrist cuffs that I made with the same material as the corset.

Amphitrite’s Trident

The trident started as a cheap plastic trident costume prop from Amazon. (Click here for trident) It comes in several pieces that you screw together and is decent but a little flimsy. I wrapped the corset and wrist cuff fabric around it, and added swirls of Worbla around the handle to give it a lumpy texture like it was a piece of driftwood. Then I painted a light layer of gold over all that.

I raided our shell collection for the details and used a real horseshoe crab shell, along with some random jewels and a piece from a broken earring. Everything was added on with a LOT of hot glue.

Mermaid Hair

To get my mermaid hair, I first crimped all of my real hair with a 3 barrel waver. (like this one) Then I added a blue and purple hair extension to the back. The extension was from Shein and cost a whole $4. I was totally surprised by the quality, as it was exactly what I needed.

The trick to using the waver is patience. It takes me over and hour to do my whole head, but the effect is worth it, and it will stay like that until I wash it out. You have to crimp a section, then move the crimper down and line up the last wave with the first barrel. If you don’t do that, the curls come out lumpy and uneven. You can see a bit of the technique in this reel here:

Mermaid Makeup and Scales

I change the eye makeup up a bit every time I do the look, but the main thing that says “mermaid” about the makeup is the scales. To get the look you’ll need a piece of fishnet. I cut up a fishnet stocking, but you can also just pull the stocking leg over your head and use it that way.

I hold the fishnet tight against my skin, then spray it with color hair spray. I used blue, but you can use any color. You’ll get defined scales from just that, but to give them a sheen and make them blend, I add shimmering eyeshadow on top. You can see how I do my scales in this reel, which also has all the makeup used listed.

The final thing I added just to put it a little over the top is the color contacts. The creepy eyes are Green Firecracks contacts by MocoQueen. Click Here and Save 10% with code SEWGEEKMAMA

Ready-Made Sea Siren Costume

If you got all the way to the end of this and are feeling overwhelmed and just want to buy a costume that is ready-to-wear, my friend Lori got the Dark Sea Siren off Amazon and it actually looks really good in person! This was the costume I kept eyeing to buy if I wasn’t going to make one. Click here to find the Sea Siren on Amazon.

About the Author

Candy Keane is a digital content creator and long-time cosplayer, most well-known for being on the cover of the Star Wars documentary Jedi Junkies. After making costumes professionally for over a decade, she now writes about about geek culture and mom life, and continues to cosplay for fun, while sharing her love of costumes on Instagram @SewGeekMama. Her first children’s book, I’m Going to My First Comic Convention, was published in 2020 and won a Story Monsters Approved award for Excellence in Literature.

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