I first hinted to this post a while back on Instagram, I completed this DIY in time for my trip to Kauai this past spring and couldn’t be happier with this first try at making a bikini!

This was my first attempt at making a bikini and by no means am I a good seamstress; decent is probably where I would land on a scale of sewing professionalism.  I would not recommend swimming in this set as it does feel a bit flimsy but I believe it can be easily remedied with a thicker swimsuit material, but it is absolutely divine to lay out in that holiday sun! I was inspired by Marysia Swim and her iconic scalloped edged bathing suits. They’re super pretty, feminine and gorgeous; and I have been lusting after a set for quite some time; I would love to own any of them they’re all so beautiful! Granted those bikinis are out of my budget range so I went to my usual solution to most fashion dilemmas which is trying to make one myself and to put my DIY skills to the test. I love the delicate feminine touch the scalloped edge gives to the bikini and it looked picture perfect for photos on my recent vacation. I chose to make it in black for easy thread matching, but would love to recreate a halter style of this bathing suit in white or a nice rust color!

TIME | 3+ Hours

COST | $10

DIFFICULTY | Some experience sewing required

*** Unfortunately I don’t have perfect documentation in photos of the top portion but I’ll include instructions below so hopefully you guys will be able to piece it together and create it. If things are unclear be sure to comment below and I’ll try my best to clarify them!

What You’ll Need:

  • Swim Suit Material (lycra/nylon base)
  • Matching Thread
  • Sewing Machine
  • Elastic (4mm for the ties, 10mm for main band on the top)
  • Chalk + pattern


  1. I started by creating a pattern out of other items in my closet, this is a common technique I use when I don’t have a commercial pattern. I used a cheekier pair of bikini bottoms to get the rough shape of my pattern piece and also a bralette to get the top. I then sketched a scalloped edge with the circles being around 1″ in diameter around the edges to create the scalloped edge on the pattern.
  2. Cut out two pieces of each pattern piece so everything can be lined and to have no visible raw edges, this will also help in adding extra support and structure to the pieces.
  3. Cut out long stripes of the swim fabric to encase the elastic straps, you can follow a tutorial here, be sure to stitch with a zigzag stitch, this will allow for continuous stretch
  4. Starting with the bikini top, stitch in the breast darts on all pieces, making sure you do the opposite for the inside pieces
  5. With the bad sides facing together, pin in the straps and  reinforce the straps to the inside panel of the cups with a cross formation, doubling up and back stitching over it a few times, repeat for all straps
  6. Sew around the perimeter of the cups making sure to double back on the strap area for extra reinforcement. You want to stitch away from the lowest points of the scallops and in a little bit as to create a nice triangle border with a zigzag stitch on the cups
  7. Take the wider piece (should be 4x the width of the final strap plus a little bit) for the under bust band, fold in half and zigzag stitch the length of the fabric and then turn it inside out so the raw edge will be on the inside.
  8. Take the band and fold it in half again but pinning the raw edge of the bottom of the cups sandwiched between and straight stitch across the band to attach the cups all together.
  9. For the back of the bikini I wanted it to criss-cross, so I trimmed by under-bust band to a desired length then folded it over to create a loop in which the straps would feed through, double stitch the loops for security
  10. Feed through the straps in a criss-cross pattern and tie off the ends of the straps, and that is your top done!
  11. Moving onto the bikini bottoms, put the good sides together and stitch the crotch area
  12. Flip the bottoms inside out and pin in the side tie straps as you did for the top, sandwiched between the two scalloped edge bottom pieces
  13. Reinforce the straps to the inside panel of the bottoms with a cross formation, doubling up and back stitching over it a few times, repeat for all straps
  14. Sew around the perimeter of the bottoms through both layers and double back around the straps again for extra reinforcement with a zigzag stitch

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  1. That bikini looks absolutely beautiful! Bikini’s are really not difficult to do, if you’re used to sewing lycra as the fabric behaves slightly differently than other fabrics. But lycra is great when you don’t want to finish the edges like the scalloped edge here! The pics are beautiful and it is a great DIY!

  2. Hola! I am fron PR so I know some english but not very well and I am trying to read I am still not sure what mean but I wish I can see the video is more easy for me to understand uhmm. Do you have any video sobre how to cut scallop and I am worrying the fabric lycra scallop will fall down?? And how to cut scallop and sew bra (no triangule).

    1. Hi Anissa! Welcome! Unfortunately I didnt take any video footage but hopefully I can clarify on some of your questions with this response! To cut the scallops you just cut them with a pair of sharp fabric scissors. Nothing fancy, if you’re using bathing suit material it will not fray so you don’t need to finish the edges. I recommend make a bikini that was ties so you can adjust it to fit your body. Because the material at the scallops has no additional support (ie. like an elastic behind it) it should lie against your skin with out any problem and look fabulous 🙂

  3. Hi there

    How did you measure and sew the elastic for the top. Did you see it directly ononline straps and then turn them out. Or did you make the straps and then feed it through.

    Thanks for the advice.
    Such a fab DIY.

  4. Hi there

    How did you measure and sew the elastic for the top. Did you sew it directly onto straps and then turn them inside out. Or did you make the straps and then feed it through after turning them out.

    Thanks for the advice.
    Such a fab DIY.

    1. Hi Louisa!

      I measure the elastics to be the same length as the straps. So the way I did it was fold the strap material into a tube inside out, please the elastic on the side of the raw edges and sew a zigzag stitch. the tube to elastic ratio should be the elastic width is 1/2 or a third of the folded strap material. Flip inside out and press with a light ironing job. Hope that helps!


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