Girl mermaid outfits

50 of the Best Halloween Mermaid Costume Ideas for Little Girls with Big Imagination

Andy Jones Costumes, Halloween

Halloween is right around the corner which means it’s time to find the best Halloween mermaid costume ideas for little girls. Nearly every girl dreams of becoming a mermaid at some point in her life, so it’s no surprise that we can take advantage of this special holiday by letting them live out their mermaid dreams to the fullest! Whether the little girl in your life wears sequins, makeup, a wig or something else inspired from under the sea, she is sure to bring all the mermaid vibes with her in style this Halloween and stand out from the crowd.

From mermaid hair and flippers to glittery manicures and shimmery makeup, there isn’t one single element of the whole mermaid lifestyle that we don’t love, especially on Halloween. Halloween is a time to dress up as anyone or anything that you want without any judgement. Little girls get so excited about becoming princesses, mermaids, unicorns and more which is why I’ve put together this epic list of some of the best Halloween mermaid costume ideas for little girls.

These mythical creatures are considered to be half-human, half-sea creature captivating our imaginations for as long as we can remember. You may easily feel overwhelmed at the task of browsing hundreds of mermaid costumes, but when your little girl asks if she can be a mermaid for Halloween, don’t stress we have you covered. There are numerous little girl mermaid Halloween costumes she can choose from. She can choose something as simple as a teal traditional mermaid outfit to a spooky vampire mermaid or even a hip non-traditional mermaid.

With Halloween coming up, it’s time to get serious about perfecting your little girl’s costume and making all her mermaid dreams come true. Here are 46 of the top Halloween mermaid costume ideas any little girl will flip their little mermaid tail over.

The 50 Best Halloween Mermaid Costume Ideas for Little Girls of All Ages

Padete Mermaid Princess Costume with Sequins

Your little girl will look darling dressed up with this Little Mermaid sequin costume. This costume features a pull-over style that’s easy to take on and take off with a stretchable back and skirt design. It includes the mermaid dress, a purple rhinestone tiara, purple gloves, purple gem earrings and necklace and a matching wand!

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A Simple Blue Sequin Mermaid Costume for Little Girls

This polyester mermaid costume is simple, yet stunning. It features a full one-piece sequin dress with mesh to separate the mermaid top from the bottom. The middle is see-through with matching blue mesh detailing as well as mesh on the shoulders. The blue sequin detailing is eye-catching and flashy for a simple mermaid costume that shines.

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Mermaid Barbie Costume Fit for All Occasions

What little girl doesn’t like to pretend they’re both a mermaid and a Barbie? This two-in-one costume features a mermaid-inspired tress with a tulle tail hem and all the elaborate jewelry pieces that mimic their favorite Barbie. This costume also comes with a coordinated headpiece to complete this ultra chic look.

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The Little Mermaid Ariel Costume

This Little Mermaid costume for girls is made from polyester that has an almost satin-like material that’s perfect for both Halloween and every-day play. The dress has a purple top just like The Little Mermaid’s with Ariel on the front and then flows down with a blue attached skirt and purple tulle for the tail.

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A Magical Mermaid Outfit for a Deep Sea Adventure

Does the little girl in your live crave adventure? This magical mermaid costume is absolutely adorable featuring a printed seashell bikini top, a printed fish scale skirt and glitter tulle for the fins. It also includes a starfish hair piece with attached pearl accents and a claw clip as well as a boa to mimic seaweed. This is a great under-the-sea adventure costume for the little mermaid lover in your life.

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Mysterious Mermaid Character Costume

This elegant mermaid costume is full of detail with its dark purple and blue intricate bodice. The dress features a bold, velveteen material that provides a little extra stretch for comfort and will have your little girl standing out from the crowd. This is a go-to option if the little girl in your life wants to be a mermaid, but not look like The Little Mermaid character.

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An Enchanting Mermaid Costume for Children

Is the little girl in your life ready to transform into the cutest creature running around town trick-or-treating this Halloween? This beautiful pale purple long sleeve metallic sequin knit features an elastic neckline, a seafoam green metallic sequin skirt and a widening tail fin at the bottom. This costume also includes a gorgeous seashell plastic headband and a seaweed boa to complete this mermaid costume in style.

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Play Tailor Swimmable Mermaid Tail Costume

Need a hand (or a fin) with a costume idea this year for your mermaid loving little girl? This premium quality mermaid tail is made from a super stretchy, smooth and breathable material that’s perfect for swimming and for Halloween photos. It comes in a variety of colors to choose from to fit your little girl’s personality perfectly.

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Yellow Sea Mermaid Dress and Headband

This gorgeous aqua and yellow mermaid costume is fit for an underwater adventure. This yellow sea mermaid costume includes the dress and a headband to complete the whole mermaid look. The bottom of this costume even has an adorable gold fin that stays puffed out so walking won’t be a problem in this adorable costume.

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A Magical Mermaid Costume Idea for Little Girls

Is the little mermaid in your life ready to take on the half-human half-sea creature life? This beautiful blue mermaid costume features a long sleeve style dress with tulle sleeves, a star on the chest, flowers running down the waist and skirt of the dress and ending with a beautiful purple striped fin that flares out.

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Little Mermaid Princess Dress Up Costume for Kids

Available in both toddler and little girl sizes, this darling Ariel costume is fit for a mermaid princess! This costume features a shimmery dress with a purple top and purple tulle. It has a teal bottom with mermaid scale detailing and transitions back to the purple tulle to complete the mermaid tail bottom. It also comes with a princess tiara!

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A Beautiful Mermaid Princess Kids Costume

This gorgeous dress is green and teal and features a boat neck neckline with shimmery detailing and glittery fabric. It has long sleeves that are tulle and a mermaid scale attached skirt that flairs out at the bottom into a mermaid tail. It doesn’t include a tiara; however, you could easily find a tiara if you’re little one wanted to become a princess and a mermaid all in one.

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Sparky Sequin Sea Princess Costume

If the little girl in your life loves all things shimmer and shine, this mermaid costume is the perfect choice. This sparkling costume is bright, colorful and straight from a fairytale. Giant multi-colored sequins make up the scales of this intricate costume along with a sparkly aquatic mermaid top, ruffle sleeves and a layered tulle fin.

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Disney Ariel Fairytale Costume for Little Girls

Ariel is one of the most famous mermaids that every little girl knows and loves. This costume is great for both Halloween and imaginative play. It features a purple upper part with a large image of Ariel and a teal bottom with a touch of purple tulle at the bottom.

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Fancy Sequin Mermaid Princess Costume

This unique mermaid costume is made from a non-itchy and comfortable fabric with sequin detailing to resemble the ever so popular mermaid outfit. This one-piece costume is great for Halloween, birthdays, parties and dress-up play. It includes the gorgeous dress and headwear.

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Three-Piece Mermaid Swim Bikini Set

If you want a little more bang for your buck, you can get your little mermaid lover a swimsuit that can also serve as her Halloween costume. It features a purple top with ruffle sleeves, a green mermaid scale bottom and a green coordinating mermaid scale tail. The tail is even hollowed out at the bottom to make it easier to walk around in.

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Adorable Pink Shiny Mermaid Skater Dress

This polyester and spandex dress features a luminescent material that looks super sleek and shiny. This skater dress is perfect for Halloween, dress-up or even everyday wear. It’s also available in numerous colors to fit the little mermaid in your life’s own unique style and personality. Choose her favorite color and she’ll be so excited to rock her new mermaid dress for all her friends to see!

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Beautiful Mermaid Princess Short Tulle Dress

This beautiful costume dress features a very silky elastic fabric top in green that resembles the scales of a mermaid tail with a silver ribbon and a large matching green bow at the waist. It has a soft tulle green bottom that’s perfect for any season. Layer it in the cooler months with a jacket and tights or wear it as is in the warmer months. It’s a beautiful dress your little mermaid will absolutely adore.

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Red Little Mermaid Wig for Halloween or Imaginative Play

Is the little mermaid lover in your life ready to rock the iconic red wig for Halloween? This gorgeous red mermaid wig is made of long, luxuriant red synthetic locks that will add the finishing touches to any mermaid costume she wears. Style it any which way she wants and she can even wear it after Halloween for pretend play.

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Fancy Dress-Up Mermaid Costume for Little Girls

This beautiful one-piece multi-tone mermaid costume will be a huge hit for Halloween! The costume features an illusion neckline with tulle long sleeves and printed ocean creatures, beads and flower appliques throughout the bodice. It’s made from a stretchy material for a comfortable fit for most body sizes and zips in the back for easy wearing.

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Comfy Stretchy Knit Mermaid Costume

This elegant mermaid costume mimics that of an adult’s body-con dress. This sophisticated style dress features a polyester stretch knit fabric that’s easy to pull on and take off. The pullover top features a ruffled boat neckline, three-quarter length sleeves and the skirt has a zipper backing and flairs out at the bottom. Also included with this dress is a starfish hair clip for the ultimate deep-sea diving accessory.

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Little Girl’s Mermaid Tutu Dress with Headband

This mermaid tutu dress is handmade with a blue and purple tulle skirt and a stretchy fabric for the top of the dress. It has purple satin-like ribbon straps and a clam shell and starfish patch for the main centerpiece on the dress. Also included is an adorable pink starfish headband that matches perfectly.

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Two-Piece Mermaid Princess Flower Costume

This handmade costume features a flower top and a fishtail tulle skirt. The top is decorated with large purple flowers and the skirt is decorated with shiny stones and purple and blue tulle perfect for a mermaid party or Halloween costume.

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Adorable Baby Mermaid Infant Costume

You don’t see many baby mermaids out there which is why this costume is so adorable and unique. This sleeveless dress is made from polyester and has a back zipper, foam applique seashells and a tulle ruffle hem. It has all the mermaid details including the bottom of the dress having green scales and a foam starfish alligator hair clip to complete the look.

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The Little Mermaid Disney Ariel Costume for Kids

This authentic Disney mermaid costume features a sequined bodice with a sheer organza overlay. It has a silvery shell brooch, a pleated mesh bust, a fitted mermaid bottom with a glittery scaled pattern and a ruffle peplum split for the tail. This elaborate costume is perfect for the mermaid princess on Halloween night.

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Disney Ariel Fantasy Nightgown for Girls

This pullover style nightgown can be worn both for bedtime, playtime and Halloween. It’s a short sleeve dress with an elastic waistband for a flexible fit and printed graphics featuring the iconic mermaid herself on the front. This is an officially licensed nightgown that your very own little mermaid may never want to take off.

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Four-Piece Mermaid Bathing Suit for Swimming

This mermaid costume idea has it all. This mermaid outfit includes a hot pink ruffle bikini halter top, matching hot pink bottoms, a rainbow printed mermaid tail and a flower garland headband. Choose from six colors and five sizes to find the perfect swimsuit for your little water lover.

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Sleeveless Sparkly Mermaid Costume for Little Girls

Mermaids are known to be colorful, sparkly and stylish. This polyester knit mesh costume will bring all of her mermaid dreams to life. It features clear flesh-tone mesh yoke for straps, a magenta bodice covered in sequins, a metallic fitted green skirt with a printed scale pattern and a ruffled organza tale at the hemline.

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Gypsy Mermaid Princess Layered Costume

Your little mermaid will be hearing the ocean calling her name when she wears this stunning mermaid princess dress. It has sort of a gypsy vibe to it with the layering and shiny beaded detailing. The top is lavender tulle with a Velcro closure at the back of the neck and a lavender purple and green organza bodice. The aqua skirt features silver glitter scales and two foam tail pieces.

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A Simple Mermaid Costume with Starfish Headband

This costume is simple, but makes a statement. It features a long sleeve white top with a seashell chest and a teal sequined bottom that flairs out into a glittery teal tail. The sparkly sequins will shimmy and shine whenever she walks. This costume also includes a starfish headband to match!

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Adorable Infant Mermaid Romper Outfit

This adorable baby girl mermaid outfit features a pastel purple bow and halter tip with a shimmery soft romper that looks like little mermaid scales. It’s suitable for swimming and will also be adorable for baby pictures. This costume also has a tutu bottom that will make your little baby the most beautiful mermaid princess in town.

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Little Girls Sequined Mermaid Scale Ballet Tutu

This ballet leotard dress is made from polyester, mesh and sequins. It has wide shoulder straps that are also sequined and a pink and black scale base leotard. It also features a two-tiered ruffled mesh tutu with shiny sequins around the hem. It’s perfect for dance class, performances, Halloween or everyday play.

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Traditional Teal and Purple Mermaid Costume

If your little one loves to play dress-up, this adorable costume has it all. It features a teal and purple mermaid scale bodice with a solid teal middle to break up the seashell top from the tail. It has long sleeves that are made with purple mesh and a matching fin that flairs out at the ankles.

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Ultra Prestige Ariel Wig for Children

Made from synthetic fibers, this red child’s size mermaid wig is both bold and beautiful. It features long luscious locks that are curled at the bottom to mimic Ariel’s hair from The Little Mermaid. The wig also has a faux starfish barrette and will be the icing on the cake when worn together with her mermaid costume.

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Full-Length Mermaid Costume for the Pink Lover

Does the little girl in your life love the color pink? Does she also dream of becoming a mermaid? Now you can bring her wildest dreams to life with this beautiful pink mermaid costume. This costume features an all pink dress with ocean décor accents and a fin skirt. The detailing of this dress is impressive and will make her feel so magical whenever and wherever she wears it.

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Little Girls Metallic Fish Scale Leotard

This leotard is made from a polyester material with long purple sleeves, a round purple neckline and a green and black printed scale pattern body. It has a glittery appearance with a stretchy and soft fabric for comfortable wear. It’s suitable for gymnastics class, dance and performance or even just around the house.

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Shiny Fish Scale Mermaid Leggings

These stretchy leggings are every mermaid lover’s dream pants. They are made with both a polyester and spandex material with an elastic waist for a comfortable fit. These leggings are versatile and feature a mermaid print scale design that’s soft, comfortable and stylish.

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Glittery Mermaid Fish Tail Princess Costume

Elsa meets Ariel with this beautiful princess dress. This dress is made of polyester and spandex and features elastic wrinkled shoulder straps, a glittery bodice and is decorated with sequins. The wide fishtail hem is layered in blue that almost resembles Queen Elsa’s princess dress from Frozen. It’s perfect for parties, photoshoots, birthdays and more.

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The Ultimate Disney Princess Dress Up Trunk

Does the little girl you know love playing dress up? If so, this Disney Princess Ariel and Aurora trunk will have her dressing up as her favorite Disney princesses from head to toe. This trunk comes complete with 11 unique pieces including 2 princess dresses, 2 sets of necklaces and earrings, 2 princess tiaras and a character trunk to store all her dress-up costumes inside.

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Sequin Party Dress for the Mermaid Lover

This adorable mermaid princess costume comes complete with everything your little mermaid lover needs to transform into her favorite mythical creature. With a pullover style dress and a stretchable back and skirt design, your little girl will be styled in comfort. This costume also includes beautiful gloves, a tiara, necklace, clip on earrings and even a wand.

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Glamourous Spectra Voldergeist Wig for Any Costume

If your mermaid lover isn’t a fan of wearing a red wig whether for Halloween or for dress-up play, this glamourous Spectra Voldergeist wig is a great alternative. This is an officially licensed Haunted Spectra Vondergeist wig fit for a child and is a great accessory to top off any costume.

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Aquaria the Mermaid Costume Dress with Headband

This Aquaria mermaid costume features an attached seashell top, a shiny blue tail and whimsical tulle sleeves. The mermaid tail sticks out in the back to make it easier to walk around in. It also includes a matching seashell headband to complete the whole look.

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Mermaid Dress Up Costume with Matching Doll Dress

Does the little girl in your life have a doll at home she loves to play dress up with? This magical mermaid princess costume was made for everyday play with no buttons, zippers or ties which is perfect for frustration free play. This costume also includes a matching doll dress that fits dolls or animals 16-20 inches in height. Now your little girl can match her doll in her favorite new mermaid costume!

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Disney’s The Little Mermaid Costume with Bag

This beautiful Disney princess costume features sequins, glitter detailing, tulle sleeves, shimmer details and a heart shape image of Ariel and her pal Flounder. This adorable costume also includes a matching Ariel bag in the shape of a dress with beaded handles and matching shimmery detailing.

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Baby Girl Sequin Mermaid Romper

Dress your sweet baby girl in an adorable mermaid romper for your next upcoming event. Whether it’s for Halloween, a party or for pictures this purple and green bodysuit will have everyone looking her way and complimenting her beautiful little outfit. The top features purple sequins and a purple ruffle sleeve while the bottom features a ruffle tiered green and black mermaid scale to represent a mermaids tail.

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Melissa and Doug Role Play Mermaid Set

Now the little girl in your life can play dress up or get ready for a night of trick-or-treating in her new Melissa & Doug mermaid role play set. This set includes a beautiful teal mermaid gown with flared tail and a seashell tiara. It’s the ideal look for pretend play or for Halloween.

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The 50 Best Halloween Mermaid Costume Ideas for Little Girls Who Are Mermaid Obsessed

This Halloween, celebrate your child’s own unique personal style and imagination. Whether they want to be a princess mermaid, Ariel or their own version of a little mermaid there are several costume ideas to choose from. One thing to consider when picking out the perfect costume for the little lady in your life is to decide if it’s weather appropriate. What will the weather be like while trick-or-treating? Will you have to find a coordinating layering piece to go over her mermaid costume? No matter what the weather holds, you are sure to have tons of inspiration from our list of the best Halloween mermaid costume ideas for little girls with big imaginations. Happy Halloween!

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About the Author
Andy Jones

Andy focuses on getting readers familiar with the latest and trendiest hairstyles. There’s pretty much no style she has yet to try, and her mission is to help everyone find the perfect look they seek. When Andy is not gushing about hairstyles, she spends most of her time reading through her giant collection of sci-fi books or watching old Star Trek shows. See all articles from Andy.