Free Girls Bikini Bottom Pattern
Nothing says summer like the first swim at the beach or pool! This free girls bikini bottom pattern is a great beginner sewing project and an easy introduction to sewing swimwear with stretchy fabrics. The free Size 3 pattern lets you try the construction before moving on to the complete multi-size pattern. If you need additional sizes, the full premium PDF sewing pattern includes girls sizes 2–14 with detailed instructions and optional lining. Whether you’re sewing your first pair of swim bottoms or making matching swimwear for the whole family, this simple pattern is quick, comfortable, and uses very little fabric.
Girls’ Bikini Bottom Sewing Pattern
🎁 Free Download
Download the Size 3 girls bikini bottom pattern free and try sewing swimwear with minimal fabric and simple construction.
Download the FREE Size 3 Bikini Bottom Pattern →
✨ Want More Sizes?
The complete printable PDF includes:
- Girls sizes 2–14
- Layered PDF (print only the size you need)
- Optional lining instructions
- Full elastic cutting guide
- Professional printable step by step instructions
Shop the Girls Bikini Bottom Pattern (Sizes 2–14) →
Supplies
You will need Lycra or Spandex fabric with at least 75% stretch. If you are not sure how to measure stretch factor, make sure you get my printable chart to take with you to the fabric shop. Those of you who are not near any fabric shops should consider buying online: Where to buy lycra and spandex
- Main fabric – Sizes 2 to 7 need 3/8 yard (0.25m), and sizes 8 to 14 need 1/2 yard (0.45m)
- Optional swimwear lining – 13″ x 15″ (35cm x 40cm). This usually comes in flesh or black and is great for preserving modesty and giving a professional finish to your bikini bottom.
- 3/8 inch swimwear elastic. Sizes 2-5 will need 1 yard (0.90m), and sizes 6-14 will need 1 1/4 yards (1.10m). The exact cutting instructions are contained within the pattern.
Make sure you choose a good brand of swimwear elastic that is chlorine and sweat-resistant. Don’t choose a cheap, overly stretchy elastic, as you won’t get good results.
How to Make a Bikini Bottom (Step by Step)
Girls Bikini Bottom Sizes
The complete PDF sewing pattern includes girls sizes 2–14, making it perfect for sewing for toddlers through older children. If you’d like to try the pattern first, you can download Size 3 free above.
A full measurement chart is included in the complete pattern so you can choose the correct size.
Step 1- Crotch Seam
Put the front and back together with RIGHT sides facing together and match the raw edges at the crotch. Stitch across with either your serger or regular sewing machine.
If you are using a regular machine, don’t forget to use a stretch needle to prevent skipped stitches. (Read how to sew Spandex and Lycra with a regular machine for extra tips on getting nice stitching.)
Step 2 – Lining
Lay your bikini bottom on your worktable with the BACK wrong side facing up. Place the lining on top of the BACK, matching the raw edges of the crotch. Swimwear lining usually doesn’t have a right or wrong side, but if it does, it should be the wrong side facing up.
Stitch across the crotch through all 3 layers.
It may seem a little strange to be stitching the lining to the back, but you will be flipping it forwards in the next step. All will be revealed!
Flip the lining to the front so the crotch seam is hidden. Baste the front to the front lining all the way around the edge. A simple straight stitch will do, as this stitching will be hidden in the construction.
Step 3 – Side Seams
Fold the pants with the RIGHT sides together and stitch the side seams with a 1/4 inch (6mm) seam allowance.
I used a narrow zig-zag ( width 1 and length 2.5) and then did a wider zig-zag on the edge (width 4 and length 2.0) to strengthen the seam. Further Reading: How to Sew Lycra
Step 4 – Elastic
I have a separate tutorial on how to sew elastic in the legs since there are a few steps involved. You will use the same method for both the waist and the legs. Read the full article: How to sew elastic in leotards and swimwear
To summarize the elastic steps, you will:
- Mark the leg holes and waist in quarters.
- Stitch the elastic in a loop and mark that in quarters.
- Match the quarter marks of the legs or waist and zig-zag through the center of the elastic.
- Turn the elastic in to form a hem and zig-zag over the edge.
In Conclusion
Now you know how to sew a girl’s bikini bottom using this easy beginner-friendly pattern. If you’re new to sewing swimwear, start with the free Size 3 pattern to practice working with stretchy fabrics, elastic, and simple swimwear construction.
Once you’re ready to make more, the complete Girls Bikini Bottom Pattern includes sizes 2–14, making it easy to sew comfortable, professional-looking bikini bottoms for girls of all ages. Pair them with your favorite swim top and enjoy creating custom swimwear in fun prints and bright summer colors.
If you enjoyed this tutorial, be sure to explore my other swimwear sewing tutorials, including how to sew elastic in leotards and swimwear, how to sew Lycra, and my collection of girls’ swimsuit and leotard sewing patterns.
Author - Luisa Clare
Luisa Clare is the founder of Treasurie, a sewing and crochet education platform offering step-by-step tutorials and printable patterns. With over 15 years of experience in dressmaking, pattern design, crochet, and craft education, she specialises in teaching beginners through clear, easy-to-follow lessons. Her tutorials and patterns are used by home sewists and crocheters worldwide to build practical skills and confidence. Learn more about Luisa and Treasurie.
