What You'll Need:

1 yd. Green Foil Mermaid Bodre (Or Fabric of Choice)
1/2 yd. Holographic Silver Bodre (Or Fabric of Choice)
1 yd. of Interfacing
1-Pale Pink or White T-Shirt
Foam Tiara Silver Glitter
Self-Stick Holographic Gems
2 yds. 5/8" wide Satin Ribbon Emerald Green
White Paper Roll (30" x 30")
4" -- 3/4" Wide Velcro or Interlock Tape
Hot Glue Gun
Glue Sticks
Tape Measure
Scissors and Fabric Pins

Difficulty Level: Beginner
Approximate Time: 60 Minutes

How to Make a Mermaid Costume

Have fun under the sea with a Mermaid costume! Make a splash on Halloween or at any event with a no-sew shiny tail fin, mermaid top and a foam princess tiara.

You can find the Mermaid costume and tail templates right here!
  • 1 Create the tail

    1. Cut out the costume pattern using the fabric.

    2. Keep the pattern folded on the center line and draw a straight line down 5" from the mark at the end of the waistline. Make a pencil mark right on the center line fold where the bottom of the ankle falls. Draw a straight line down from the bottom of this 5" line to the ankle mark on the folded center line. Next, freehand draw a long slightly curved line just on the outside of this long straight line, about 1 1/4" away from the straight line at its center. Make sure this is tapering closer as the curved line touches both ends of the long straight line. Make sure to round off any sharp edges along this long curved line from waistband down to point at ankle. Keep folded and cut through both layers along this long curveed line from ankle point to waistband.

    3. Pin the pattern onto 2 layers of the green foil Mermaid fabric-right sides together. Make sure the pattern on the fabric of both layers is going in the same direction, pointing downward from the waistband edge. Cut out two layers together with an added 1/2" seam allowance added on all edges for gluing the seams together.

    4. Pin the same pattern at the interfacing fabric and cut out interfacing along the edges of the pattern. DO NOT add a seam allowance. Keeping the 1/2" seam allowance showing all around it, tack the cut out piece interfacing with tiny dots of hot glue in the corners and spaced out along the edges onto the back-side of one layer of the Mermaid fabric.

    5. Keep right sides of the fabric touching and leave a 6" long section open and unglued at the bottom point of the tail where the tail fin will be later. Run a line of hot glue between the two layers along the top waistband edge and press together to create a glue seam. Next, leave a 1" open and unglued section for the ribbon ties on both sides right under the glued waistband. Run a hot glue line between the two layers from 1" below the waistband down to 6" above the bottom point and press together on the glued seam. Let the glue cool/dry and then turn the Mermaid tail right side out so that the shiny scales are facing out.

    6. Glue two 24" lengths of 1" wide green satin ribbon 1/2" into the 1" openings on both sides of the waistband. Glue both of these openings closed with seam allowance on both layers tucked into the glue seam.

    7. At bottom 6" tail point separate the two layers and use hot glue to fold and tack the 1/2" seam allowance all along the edges here onto the back side of the fabric. Do this on both layers still keeping the layers separated from each other on this bottom 6" point.

  • 2 Create the tail fin

    1. Pin the pattern provided onto two layers of the holographic silver fabric with back-sides of the fabric facing out and the right-sides touching. Add 1/2" seam allowance on all edges and cut out the tail fins. Use the same pattern to cut out a tail fin shape from the interlacing fabric. Do not add a seam allowance to the interfacing piece when cutting it out.

    2. Keep the 1/2" seam allowance on the back-side of the holographic fabric showing all around and tack the interface piece onto the backside of one layer of the holographic silver tail fin. Hot glue tiny dots spaced out around the edges.

    3. Leaving a 4" unglued open edge at the top center of the tail fin to turn right-side out, run a line of hot glue a few inches at a time all around the right-side edges of the two layers of holographic fabric and press the layers together as you go to create a glue seam. Let the glue cool/dry before turning the tail fin inside out so that the shiny holographic right-side is now facing out.

    4. Slide the tail fin in between the two pointed layers at the bottom of the Mermaid tail. Make sure that it is centered and glue the fin into place first on the top layer, let the glue cool, flip over and glue on the other side the same way.

  • 3 Create the Mermaid top

    Measure around the bust of the child. For your length, take the bust measurement and add 3" to allow for the seam allowance and overlapping at the Velcro® back. Cut a rectangular strip of holographic silver fabric that is your length x 9" wide. On each end of the strip, fold and glue a 1/2" hem along each of the 9" edges, back-side glued onto the back-side of the fabric. Fold the fabric in half the full length of the strip with the back-side facing out. Run a line of glue all along between the two layers at the edge to create a long tube of fabric. Let the glue cool/dry and then turn the tube right-side out with the shiny side facing out. Glue each end of the fabric tube closed. Glue one 4" long strip of Velcro® at each end of the strip so that they will overlap and stick to each other. Make a 1" x 2 1/4" tube out of the same holographic fabric and glue it together on the inside, looping around the front center of the Mermaid top. Cut a 48" length of 5/8" wide green satin ribbon to slip through this front center loop, then up over the shoulders to tie behind the child's neck in a halter top style.

  • 4 Accessorize the tiara

    Stick the gems onto the foam tiara.