New This Month


Mermaid Costume

Make a splash! This costume pairs shimmery printed leggings and removable tulle-wrapped elastic bands for a showstopping tail that's comfortable enough that she can walk (er, swim) in with natural, fluid grace. Top off her look with the accouterments of an undersea princess: seashell accessories and a fishtail braid.

mermaid halloween kids costume girl sea shells

Photography: Janelle Jones

Source: Martha Stewart


Note: This costume is appropriate for children ages 5 and older. Because our costumes were assembled from household materials, they do not conform to all of the safety requirements that store-bought costumes do. Therefore, children wearing them should be supervised by an adult at all times. Make sure that your seashell crown and necklace are glued together securely and not too heavy for safety. This mermaid pairs well with our octopus costume and lobster costume for an adorable undersea-inspired group ensemble. For this project, you will need to gather an assortment of 6- to 10-inch rolls of fabric like tulle, glittered tulle, and organza (available at craft stores) in aquatic colors. When it's time to dress up, learn how to braid hair with the fishtail technique, which is done by gathering the hair into a ponytail and dividing into two sections that are crossed over with thin clusters down the length of the hair. Watch our video tutorial (on this page) to see how it's done.


For more ideas, scroll through our entire collection of kids Halloween costumes.


  • Tank-top (Primary The Tank in Azalea, $8,

  • Neutral long-sleeve shirt (Pictured: Petite Amelia Little Girls Long Sleeve Bow Top in Beige, $13,

  • Scale-printed leggings (Pictured: Frogwill Girls Mermaid Scale Leggings in Green, $10,

  • Assorted rolls of 6- to 10-inch fabric tulle, glittered tulle, and organza

  • Shoes (Pictured: L-RUN Girls' / Women's Canvas Ballet Dance Shoes in Green, $9.60,

  • Fabric scissors

  • Assorted seashells

  • Gold elastic cord

  • Hot-glue gun and glue sticks

  • Sewing needle


  1. For the tail, cut fabric rolls into 20-inch lengths. (Note: You will need around 24 rectangles per leg.) Stack three 20-inch pieces of fabric, and run elastic gold cord through the center of the rectangle (10 inches in from the edge). Each leg will require eight of these stacks of three 20-inch segments. Tie off ends of gold cord so the tail fits on the leg without sliding off.

    mermaid costume how-to step
  2. For the tiara and necklace, layout assorted shells and hot glue together. Hot glue shells to a fabric covered headband, Hot glue the necklace to a length of elastic cord.

    mermaid costume how-to step
  3. For the costume assembly, layer a colorful tank-top over a neutral long sleeve top, knotting it in front. Pair with metallic mermaid leggings secured with elastic tail, green shoes, and seashell accessories. (Optional: Style hair into a fishtail braid.)

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