Mermaid Costumes for Halloween

NancyZieman MermaidTails

Mermaid Costumes for Halloween

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NancyZieman MermaidTailsMake this mermaid costume for Halloween and enjoy dress-up all year around. The idea came from my granddaughers. After watching Doll Costume Dress Up on Sewing With Nancy, my oldest granddaughter Avery promptly asked, “Gramma, for my birthday could you make a mermaid costume for my doll and one for me too? Now, don’t make an opening for my feet, I can swim like a mermaid with a tail!”  Then I asked her sister, Luella what she would like for her birthday. Answer: “Same as Avery!” So, two mermaid sets—big and small—were the task. (Much to Avery’s dismay, I made the big-girl fish tails with openings for feet!)

MermaidCostume 18InchDoll GlamShotMy Sewing With Nancy guest and friend, Joan Hinds developed the pattern for an 18″ doll dress-up mermaid costume. You can see how we created it in sequin fabric on the Doll Costume Dress Up episode online, and you’ll find the patterns in the bookThe pattern can be scaled (pun intended) to fit child sizes, giving you matching dress-up clothes for your favorite little ones. Here’s how I scaled the design and created a mermaid tail for my granddaughters, ages six and four.

MermaidCostume TwoSizesSupplies, Fabric, and Notions

For both doll and child sizes:

For 18″ doll size:

  • 1/3 yd. sequin knit fabric
  • 1/3 yd. lining fabric
  • 11″ elastic, 1/4″ wide
  • 1/4 yd. satin fabric
  • 1/4 yd. matching sheer shimmer iridescent fabric
  • 1 yd. decorative trim
  • Ready-made Doll T-shirt
For child size 5T:
  • Tail Pattern PDF
  • 3/4 yd. sequin knit fabric
  • 3/4 yd. lightweight knit fabric for lining
  • 24″ elastic, 1/4″ wide

Create the Girls’ Mermaid Tail Pattern

  • Draw a 13″ x 20″ rectangle on Pattern Tracing Paper.

How to Make a Mermaid Tail Pattern by Nancy Zieman of TV's Sewing With Nancy

How to Make a Mermaid Tail Pattern by Nancy Zieman of TV's Sewing With Nancy

  • Place a dot at the top of the curve, 1/4″ in from edge.

How to Make a Mermaid Tail Pattern by Nancy Zieman of TV's Sewing With Nancy Note from Nancy: To alter the pattern, lengthen at top edge, and widen at left edge. 

How to Make a Mermaid Tail Pattern by Nancy Zieman of TV's Sewing With Nancy

  • Cut out the paper pattern.

How to Make a Mermaid Tail Pattern by Nancy Zieman of TV's Sewing With Nancy

Construct the Tail 

  • Place fabric wrong sides together, and cut two tails from both the sequin fabric and the lining fabric.

How to Sew a Mermaid Tail by Nancy Zieman of TV's Sewing With Nancy

  • Sew side seams and bottom edge of the tail, right sides together, leaving opening between dots as marked on the pattern piece.

How to Make a Mermaid Tail by Nancy Zieman of TV's Sewing With Nancy

  • Turn to the right side and press.

Note from Nancy: Use Point Turner to turn tail points.

How to Make a Mermaid Tail by Nancy Zieman of TV's Sewing With NancyHow to Make a Mermaid Tail by Nancy Zieman of TV's Sewing With Nancy

  •  Repeat steps above for lining, but don’t turn sewn lining to right side.

How to Make a Mermaid Tail by Nancy Zieman of TV's Sewing With Nancy

  • With wrong sides together, insert the lining inside the tail. Zigzag or serge the top edges together.

How to Make a Mermaid Tail by Nancy Zieman of TV's Sewing With Nancy

  • Fold 1/2″ of the waist fabric/lining toward the wrong side and stitch, leaving a 1″ opening for an elastic casing.

How to Sew a Mermaid Tail by Nancy Zieman of TV's Sewing With Nancy

  •  Thread the elastic through the casing, using a Clip and Glide BodkinSecure the edges of the elastic. Optional: Sew opening closed.

How to Sew a Mermaid Costume by Nancy Zieman of Sewing With Nancy

How to Make a Mermaid Costume by Nancy Zieman of Sewing With Nancy

  • Turn up a 1/4″ hem to the wrong side, folding the lower edges of the sequin and lining fabric together; topstitch.

How to Make a Mermaid Tail by Nancy Zieman of TV's Sewing With Nancy

How to Make a Mermaid Tail by Nancy Zieman of TV's Sewing With Nancy


Use a Point Turner to “stuff” the tail and topstitch to hold the stuffing in place.

How to Make a Mermaid Tail by Nancy Zieman of TV's Sewing With Nancy

How to Sew a Mermaid Tail by Nancy Zieman of TV's Sewing With Nancy

Create the 18″ Doll Top

Note from Nancy: In the Doll Costume Dress Up book, a pattern is provided for the 18″ doll mermaid top. For another option, I decided to do a quick makeover on a ready-made 18″ doll T-shirt. 

  • Create a front bodice panel and topstitch to an existing T-shirt. The shirt pictured below is for an 18″ doll.

MermaidCostume Bodice NancyZieman f

  • Cut a bodice shape from Pattern Tracing Paper. Cut one bodice panel from the shimmer overlay and two panels from the lining.

MermaidCostume Bodice NancyZieman a

  •  Sandwich the shimmer fabric between the two lining pieces. Pin.

MermaidCostume Bodice NancyZieman b

  • Sew using a 1/4″ seam allowance; leaving the lower edge unstitched.
  • Notch seam allowance at curves. Remember to clip to, but not through, the stitching line.

MermaidCostume Bodice NancyZieman d

  • Turn the bodice shape right side out.
  • Smooth the curves with a point turner tool.
  • Fold the lower edge towards the bodice panel lining, and press up a 1/4″ hem.
MermaidCostume Bodice NancyZieman e
  • Position the panel on the center front of the shirt.
  • Topstitch the folded hem at the lower edge.

MermaidCostume Bodice NancyZieman g

  • Edgestitch the bodice panel to the shirt.

MermaidCostume Bodice NancyZieman h

  • Apply as much trim as you like to finish off the mermaid costume top.
MermaidCostume Bodice NancyZieman j

Ta-Dah! Time for a make-believe swim!

How to Sew a Mermaid Tail by Nancy Zieman

Watch Doll Costume Dress Up  on Sewing With Nancy online.

MermaidCostume NancyZieman JoanHind

Doll Costume Dress Up. How to sew doll clothes and costumes. As seen on Sewing With Nancy Zieman

For a chance to win a copy of the book, Doll Costume Dress Up by Joan Hinds, please leave a comment sharing your favorite costume-sewing memory. Random winner within the continental US will be shipped a paper book or international winner will be emailed an electronic book from F+W Media.
Bye for now,
Nancy Zieman The Blog

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  • Carol
    October 25, 2016

    Would love to make my niece some beautiful clothes for her doll. She would be so excited!

  • E. Ann
    October 25, 2016

    I have made several costumes for grandchildren. Just finished a “big and round” pumpkin from the babylock projects for my granddaughter. But my favorite costume memory is a cow costume I made 20 yrs ago for my first grandchild, grandson. We passed it down to several more. And I’m certainly in to sewing doll clothes for my granddaughter!! Would love the book!! To make more memories!!

  • Robin
    October 25, 2016

    For my granddaughter’s first Halloween (she’s 10 now), my daughter and I made her a mermaid costume. My daughter took a onesie and glued seashells to it and I drafted and sewed the skirt. Since my granddaughter wasn’t walking yet, I made it long enough to cover her feet and padded the tail at the end. It was one of her best costumes so far, and she must have remembered it because two years ago she asked for (and got) one of those mermaid tails custom made for swimming for her birthday. I love Joan Hinds’ books. I have the two previous ones with the accompanying DVDs.

  • BevM
    October 25, 2016

    I have made many costumes for my daughter and granddaughter. One favorite was for the 4-H cat costume class. I sewed a mermaid outfit for my daughter, and a “cat fish” outfit for the kitty. Also, just made my granddaughter a pumpkin costume for her 18 inch doll.

  • Twyla
    October 25, 2016

    My 5 granddaughters love to have doll clothes for their doll babies. Four of them have the American Girl Dolls and have asked me to make them a set of clothes for their dolls. Would love to win the book in order to get some different ideas to make. Thanks!

  • DebbieW
    October 25, 2016

    Adorable, and to have their dolls matching too! So clever Nancy, Joan. My kids costumes were always homemade and lots of fun to make…even if some were being completed in the wee hours of the morning.

  • Deborah Herold
    October 25, 2016

    I was Senior in High School & President of the Costume Club I made a dragon costume for a play out of a green sparkly fabric and the tail was 4 feet long with horns along it & stuffed. I wonder if it still is in the school? Ha Ha That was in 1967.

  • Kathryn E
    October 25, 2016

    I have made so many costumes over my 47. years of sewing.
    I taught myself to sew when I was 19. Designing and making costumes has been my favorite sewing. I have done numerous costumes for friends and family. I have also designed and sewn belly dancing costumes and I have made Hawaiian clothing for my hula club. My favorite costumes were for a friend’s children when I was visiting her in California. The kids were enchanted by my making the patterns out of newspaper and sewing up a lady bug and a fifties circle skirt from felt. Not complicated but fun. I also loved making complicated butterfly wings for my 2 nieces while visiting them in New Zealand. The wings were satin on the under side and metallic on the front side with pearls and gold veins between the different colored parts of the wings. The wings had ribbon with click clasps to hold them on. Another great time.
    Joan Hinds has some wonder books on doll clothes. I sew doll clothes for gifts to friends grandchildren.
    I’m everybody’s favorite aunt blood-related or not.

  • Judy G.
    October 25, 2016

    I love all of Joan’s patterns. I have sewn doll clothes for many years and still learned new tricks from Joan Hinds. I would love to add this pattern book to my collection.

  • Brenda
    October 25, 2016

    I love making costumes! I made an ET costume for my son years ago and several children have worn it since then. My favorite is probably the wolf and little red riding hood I made for my two oldest granddaughters. Red riding hood was easy but the wolf was very hard and it turned out great.

  • Terry
    October 25, 2016

    For my children and grandchildren I have sometimes matched doll costumes to fit the theme. Among my favorites were a half devil, half angel for one daughter when she was two. Now she is a speech and language specialist (SLP) and teaches young children who cannot talk to use communication devices with symbols. All the SLPs at her work are doing symbols from the devices. She is good and bad so I am doing a half good witch, half bad witch. When she and her sister were young adults they chose to be Victorian versions of night and day. I wanted them to carry a basket of coal since Cole Porter wrote Night and Day but they thought that was way too much.

  • Melissa S
    October 25, 2016

    I love to make my girls’ costumes, although not this year. My oldest will use her witch costume from 2 years ago (still loves it) and the youngest is using a hand me down of her sister. My oldest – who will be 10 soon- is starting to make clothes for her dolls and her sister now too. The youngest would love to be a mermaid. When I made them mermaid blankets earlier this year, she wanted to know if it had a ‘bra’ to match

  • Arlene Burger
    October 25, 2016

    My favorite costume-sewing memory is when my 3 yr old daughter wanted to be a clown. That was 42 years ago and the first time I sewed a costume without a pattern. It turned out so cute. The fabric was satin with white and green stripes. I put bright orange ball trim around hat and arm/leg cuffs. Every time I look at the picture of so many yrs ago, it always brings a smile.

  • Jan
    October 25, 2016

    I have made a blue crayon and red crayon, matching scarecrows, bumblebee, clowns, Roman costume for a Latin class party, dragons, and–can’t remember them all. I’m sure they gave me much more pleasure than the children had from them. So much fun and happy memories. After three grandsons, I would love to have the book for clothes for my granddaughter’s many dolls.

  • Michelle Hall
    October 26, 2016

    I remember the year I made my son a Knights armor costume and my daughter a princess costume. They sure looked cute together

  • Michelle Hall
    October 26, 2016

    I remember the year I sewed a princess costume for my daughter and a knights armor costume for my son. That was before I had a serger and the silver lame I used for the armor was such a pain to deal with

  • Tina Jeo
    October 26, 2016

    I love sewing/making my daughter’ costumes. We have fun doing it together.

  • Donna Fecteau
    October 27, 2016

    When my daughter was 4, I made clown costumes for all three of us. Mom, dad, and my daughter. She loved the costume so much she wore it to bed some evenings. The next halloween my son was only a month old and I thought that I would add him as a fourth clown, however, my daughter was not happy with that plan. She wasn’t so sure she wanted to keep her baby brother or share the clown act with him. So I bundled him up, and put him in a big wicker laundry basket with a tag that said, “Please take care of this baby”. As many of family and friends, opened their doors and said they would love to take care of such a cute baby and offered to take him right in, my daughter got more and more possessive of him. By the end of the night she was firmly in love with and keeping her brother. His costume wasn’t nearly are beautifully put together as hers, or planned as well, but it had a great reception, and a great result for our family.

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