How To | Lava Girl Costume

The Adventures of Shark Boy and Lava Girl

Lava Girl Halloween Costume

My daughter recently discovered the movie The Adventures of Sharkboy and Lava Girl and made the request to be Lava Girl for Halloween. Here is a simplified version of how to create your own Lava Girl costume using felt, puff paint, markers, a shirt and pants.

(You can now view and add your own pictures of Lava Girl costumes to my Lava Girl Costumes Flickr group. Visit the group here.)


  • Matching shirt and pants
  • Coordinating yardage of felt
  • Coordinating thread (If you don’t sew use a Felt Glue, not just a fabric glue)
  • Tulip Slick Dimensional Fabric Paint in Fluorescent Orange
  • Sharp sewing scissors
  • White Chalk Marker or Chalk Wheel
  • Sharpie Marker in Black Super Permanent
  • 8.5 x 11 foam sheet in bright orange
  • Sticky or sew on velcro
  • Pink wig
  • Picture of Lava Girl for reference

Lava Girl Costume Finished Shirt

The Shirt: To start I had my daughter try on the plain pink shirt and I held up the piece felt to her with the shirt on. I then used the chalk wheel to mark the cuts I would make on the main felt piece. (My costume only has felt on the front side of the shirt and pants.) I made sure that I was marking the width of the felt to match the side seams and the length of the plain shirt.

I then had her remove the shirt and I laid it out flat on the counter and once again laid the felt piece with chalk marks on the shirt to double-check the width and length before I cut. I referenced the Lava Girl picture to see what shape to cut the felt piece along the top and marked it out using the chalk.

Using my sharp scissors, (felt can dull a pair of so-so scissors quickly and you won’t get a clean cut) I cut on my chalk marks. Next I laid the cut felt piece back onto the plain shirt to make sure it was a match in width and length. While the main cut felt piece was laying on the shirt I cut out more felt circle/lava rocks to be added along the neck and shoulders of the shirt, again referencing the Lava Girl picture while assessing how much space I had between the top of main felt piece and the plain shirt neckline.

The Belt: To make the “belt” that goes across the shirt, I cut a strip of felt the same width as the main felt piece. I laid the cut rectangular strip on top of the main felt piece and used my chalk to mark the shape of the belt piece I wanted to cut. I then cut out the belt piece. Next I used the chalk to draw a circle shape in the center of the belt and a series of smaller circle shapes to the right of the center circle. I cut these shapes out with my scissors. To give a belt some dimension I used bright orange foam and cut it slightly smaller than the overall shape of the belt. I laid the foam underneath the belt and pinned it onto the belt. Then I laid the belt in the position I wanted it on the main felt piece and pinned it down (only pin it to the main felt piece, not to the plain shirt). I then sewed the felt belt + foam underneath to the main felt piece. (The main felt piece is still not attached to the plain shirt.)

Lava Girl Shirt in Progress

Main Felt Piece with Fabric Paint Applied

Lava on the Shirt: To add the “lava” to the main felt piece I used my chalk to mark where I wanted the lava to flow. I then carefully started at the top of my main felt piece and applied the fabric paint to the correct spots on the felt. I was careful to work from top to bottom and then left to right so that my hand did not smear any of the fabric paint I had already applied. Set this piece aside to dry, preferably overnight.

Add Burned Edges to the Felt

Burned Edges: When the fabric paint was completely dry I used a black Sharpie marker to add a burned look to the edges of the felt. I carefully rubbed the marker along all the edges of the “lava”. Next I added marker to the outside edges of the lava rock pieces and main felt piece. I used a paper towel to keep my finger tips from getting black while I held the small pieces.

Finishing Up the Shirt: Once the burned edges where added to all the shirt felt pieces I pinned everything onto the plain pink shirt. Next I sewed all the pieces onto the shirt. If you can’t sew, use a good Felt Glue to adhere all your pieces onto the shirt. A felt glue is important because it actually adheres to the felt and makes it stick to the fabric. My past experience with regular fabric glue on felt has resulted in a sticky mess and the felt didn’t stick to the fabric well at all. Check the glue bottle and make sure it is recommended for use with felt.

Lava Girl Costume Finished Pants

The Pants: To cut the felt pieces for the pants I laid the pants out flat on the counter. The plain shirt I bought is long enough that it covers the top of pants, allowing me to leave the waist of these pants untouched. This was good because these pants have a drawstring inside and I wanted to leave them adjustable. I used the same technique to cut the felt pieces for the pants as I did for the shirt lava rocks. I laid the yardage of felt over the pants and used my chalk to mark where I wanted to cut. I used the Lava Girl movie picture as a reference to see what size/shape pieces I needed. My top piece goes along the entire width of the pants. The other pieces fit only into each pant leg. As I marked with the chalk and cut my pieces out I pinned them in place on the pants. This made it easier for me to see what shape to cut the next piece.

Lava on the Pants: Once all the pieces where cut and pinned in place I sewed all the pieces onto the pants. Next I used the fabric paint to apply lava to the pants. When I was finished I set them aside to dry overnight.

Burned Edges: When the fabric paint was completely dry I used a black Sharpie marker to add a burned look to the edges of the felt. I carefully rubbed the marker along all the edges of the “lava”. Next I added marker to the outside edges of the lava rock pieces, in this case they were already attached to the pants, so I had to be careful not to get too much marker on the pants.


The Wrist Guards: To complete the costume I made wrist guards. I started by measuring my daughters wrist and forearm, then I made a paper template. I used the paper template and wrapped it around her arm to get the shape I wanted, making sure there was enough overlap to add the velcro. I placed the paper template onto the yardage of felt and traced around it with my chalk. I cut out the felt pieces and then added lava using fabric paint and let the pieces dry overnight.

The next morning I added the burned edges. I then cut sticky velcro strips and added them to the wrist guards.

All the Pieces of the Finished Costume

The crowning touch to the entire costume was the pink wig I found at JoAnn’s. My daughter is in love with the entire costume. I am sure it will be comfortable and warm for her to wear for her Halloween party at school and on Halloween night!


  1. Outstanding! My 4 year old decided last spring she was going to be Lava Girl for Halloween. I assumed she would have changed her mind dozen ties by now, but that is not the case.

    You have given me some really great ideas, thanks!!

    pS: we are on our second copy of the movie, her sister wore it out 5 years ago and we are now on round II

  2. I just read how you created the lava girl costume for your daughter last year. I so wish I was that creative & skilled…but I am far from it! Wondering if you still have the costume and if you would be willing to sell it? My daughter really wants to be lava girl for halloween and I cannot find one anywhere, except on Etsy for $80. I thought talking her out of the $50 Tangled one was a good call until researching Lava Girl. My daughter is 7.
    Thanks, Susie

    • Susie,
      I wish I could say that my daughter is ready to part with it, but it still fits her and she stills wears it to play. Maybe in a few years! Good luck, I hope you can locate one for a reasonable price!

      • Is there any chance she’s grown put of it and you’re willing to sell it? What size is it? My god daughter has special needs and I can’t seem to talk her out of being Lava Girl. She is 7 and in a 10/12.

  3. Thank you for sharing your costume! My 7 yo wants to be Lavagirl this year as well. Your plan seems the most doable for this non-crafty mama. Although, finding the shirt and pants was not as easy as I expected. We are off the the craft store for the rest of the supplies today.
    Now she is trying to convince her little brother to be Sharkboy instead of a robot.

  4. Stephanie says:

    I Love the ideas you have given me alot to go off of! my 4 year old daughter is In Love with this Movie and has went back on forth on what to be but she stuck with Lava girl…Not so lucky for me tho! I need some help or idea’s for the LAVA BOOTS. that is the main things she keeps talking about and I am lost for ideas! PLEASE HELP! Thank you.

  5. thank you so much! i was searching everywhere for a lava girl costume for my daughter! i found one on ebay for $135 but that was too expensive though now at this point i kind of wish i did buy it because I’ve been trying hard to figure out how to get it perfect for my daughter for weeks. but i am so glad i just ran across this! my daughter is going to be so excited tomorrow night! and I’m excited because she finally wanted to be a girl costume!! haha thank you so mch though

  6. Thank you SO MUCH for these awesome instructions!! My daughter was watching the movie a few weeks ago, and decided she wanted to be lavagirl! As we all know, there are no off-the-rack lavagirl costumes to be found!! I followed your instructions, and her costume turned out great!! She got a lot of compliments, and I gave you all the credit!! Awesome supply list and instructions made my daughter’s dream of a lavagirl costume a reality!! Thanks so much!! :)
    If I can figure out how, I will post a pic!

    • Susan,

      I am so glad you daughter had a great night of trick-or-treating in her Lava Girl costume! I am thinking of starting a Flickr group where people can post pictures of their Lava Girl or Shark Boy costumes they made. I will work on that today. I would LOVE to see how all the costumes turned out.


  7. Alanna,

    Like the other posters here, I cannot thank you enough for the instructions for the Lava Girl costume. My 4 year old loved her costume, and as a non-crafty mom, I loved that this was relatively easy to do. When I heard people saying last night, “Hey, she’s Lava Girl!” I knew I had pulled this off. I only wish that I had thought to make my 11 month old a Shark Boy costume!

    Thank you, thank you, thank you!!

  8. I just posted the pic of my daugher’s costume on the Flickr page. Thank you so much again for the great instructions!! Have a great day! :)

  9. Hi Alanna,
    Thank you for posting your How To Make a Lava Girl Costume page!
    The directions were easy to follow. My little one really wanted to be Lava Girl for Halloween. I made the costume, she was very excited to try it on and wear it. Turned out Great! Will try to post a photo on Flickr. Thank you again!!!!

  10. Big thanks from Sweden. My 4 year old will love this!

  11. im watching the movie with my 8 year old daughter now and she said she wanted to be lava girl. her birthday is coming up and i want to buy her a lava girl costume. i looked on ebay and i found many costumes but they were too expensive. im sooooooooo glad that i looked on this site! thanks again! im going to start tomarrow!

  12. Thank you! My mom and I are making my 6 year old her Lava Girl costume now! :-)

  13. You have NO idea how much your creativity has saved me!! My 3yr old daughter has recently become obsessed with Lava Girl and has preached since the summer that she wanted to be her, at the time I figured she would change her mind come Halloween, but NOPE! Lava Girl it is… I had no clue where to get one. I tried getting her to change her mind with other options… didnt work. When I came across your site, it was like the heavens opening up! lol Im not as crafty when it comes to clothing, but your simple step by steps helped so much! I Cannot begin to thank you enough!

  14. I couldn’t have made the Lava Girl Costumes for my 10-year-old twins without your tutorial! Thanks! I would have never found costumes in tween sizes. I wonder what they will throw at me this year?

    • So happy you found it useful! My daughter just put her costume on and played in it the other day!
      Thanks for visiting!

  15. This is awesome! My daughter has loved this movie for years but I’ve never been able to find a costume for less than $100 thanks so much you have made her halloween!

  16. So freaking awesome! my 5 y/o is going to love this. Thanks a ton for sharing!

  17. Thank you so much! I cannot believe I found this tutorial! My 4 year old loves Lava Girl. I can’t wait to give this a try!

  18. Lucy'smom says:

    Thanks so much for sharing, making this for my 5yo for Halloween!

  19. Thank you for sharing this. I made this for my 5 year old for Halloween and it came out awesome. She was the hit of her block, and loves being Lava Girl.

  20. Is there any chance you would be willing to make this for my daughter? She wears size 6. I will pay you of course. She wants to be lava girl for Halloween so bad but im not crafty like this. It’s really an awesome costume.

    • Amber, I wish I could, but I get a lot of requests from my readers to do this and it isn’t really something I do. Maybe you could find a local friend or grandma who sews?

  21. Hi, I can’t sew.. At all.. Are you willing to sell your lava girl costume? Thought I’d ask before I attempt it, my daughter wears a 6.
    Thank you!

  22. Thanks for the easy directions on how to make Lava Girl costume. I don’t sew but I am crafty. It turned out great.. it was easy. She looks so cute. She’s 4 and she absolutely loves her costume. I wanted to post pictures but I couldn’t figure out how. Lol
    Anyway thank you made my life a little easier.


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