Summer=Swimsuits: Soma Bathing Suit Hack


I’m back today with my long-awaited/long-procrastinated-on Soma swimsuit hack.  During the winter, I tried all the Soma swimsuit variations (here, here, and here).  Then, I set out to make my ultimate version!  Here were my goals:

  1. Turn Bikini Variation 2 into a tankini, inspired by this suit.
  2. Add support in the form of underwires, with help from Gertie’s blog.
  3. Add polylaminate foam for coverage and modesty, as seen on sallieoh’s blog.

Let’s check out the suit:

Summer=Swimsuits:  Soma Bathing Suit HackThe top.

Summer=Swimsuits:  Soma Bathing Suit HackHigh rise bottoms.

Summer=Swimsuits:  Soma Bathing Suit HackLow rise bottoms.

Let’s talk about the bottoms, because there isn’t much to say there.  I followed the directions and made the low rise bottoms in a medium and the high rise bottoms in a small.  I used black fabric for the outside with a black lining.  I used white elastic because I wanted to order a large quantity, and I figured that would be most versatile.  I like them, but I think the next time I make bottoms, I’ll go for something with more coverage rather than this style, which is slightly cheeky.  I think the pattern for these is good–that’s just my personal preference.

Now for the top.  Here’s a small fraction of my planning:

Summer=Swimsuits:  Soma Bathing Suit Hack This is when math class (at least arithmetic) meets the real world!  I figured and refigured until I thought I had it right, and then I made pattern pieces for the front and the back trusting in the spandex to stretch right over any mistakes I might have made.

Summer=Swimsuits:  Soma Bathing Suit HackFrom left to right:  back, front middle, front sides.

So, this next part is going to get long.  Feel free to skip to the end if you aren’t interested in the sewing details, but because it’s helpful to me when others post what they did, I’m going to give you my step-by-step process (because I’m also hoping someone out there can troubleshoot my mistakes!).  This will make most sense if you have a copy of the directions in hand while reading this.  Here we go!

This was my process for the top:

  1. Starting with the bikini top part, stitch together outer fabric only as in Step 1 of the directions.
  2. Stitch together lining only as for outer fabric in Step 1.  In retrospect, I should have followed the lining instructions.
  3. Trim seam allowances back and clip curves on outer and lining pieces.
  4. Encase underwires in channeling or 1/4″ double fold bias tape (I used this since I hadn’t ordered channeling.).  Don’t stitch ends closed, at least on one side.  Leave extra bias tape at ends.
  5. Pin to inside of lining, matching bottoms to underbust seam and shorter sides to triangle seam.
  6. Hold underwires slightly open (as per Gertie) and mark with chalk or whatever.
  7. Remove underwires and sew on both sides of channeling/tape with a straight stitch.
  8. Reinsert underwires and sew ends closed.
  9. Pin polylaminate foam in place with lots of pins!
  10. Use long zigzag stitch (for me this was a zigzag with a width of 4 and a length of 2.5) to sew around the outer perimeter of the front.
  11. Use square zigzag (this had a width of 4 or 5 and a length of 1.5) to sew over seam between lower cup and underbust piece, being careful not to sew the underwires.  Sew from central triangle toward outside seam.
  12. Use square zigzag to sew on either side of center bust seam from middle triangle to outer edge.  I tried and tried to do this, but my machine kept skipping stitches and I never managed to get it right.  I had to rip the stitches out in the end.
  13. Follow steps 7 and 8 for Bikini Variation 2 in the instructions with a square zigzag (I used a width of 5).
  14. Stitch together the bottom of the back piece so it can be used as one piece.
  15. Assemble front outer fabric and then lining fabric for tankini/stomach section.  I forgot that I wanted to sew each outer piece to each lining piece and then assemble the front so it wouldn’t balloon in the water, but I don’t think it mattered in the end.  I ended up with pieced outer fabric and pieced lining fabric for the front that was not attached together.  If I wasn’t going to sew them together, though, I could have just cut two of the back pattern piece in lining fabric and saved myself some time and made the inside of the suit look a little nicer.  Oh, well.
  16. Sew front sections together wrong sides together around the edges.
  17. Layer fabric for tankini section in this order:  outer back fabric right side facing up, constructed front right side facing down, back lining piece wrong side facing up.  Pin together at sides and sew with long zigzag stitch.
  18. Flip fabric around so everything is right way out.  All side and front piecing seams should be enclosed.
  19. Use a long zigzag to sew across the front excess length (there was about 1 inch extra length on the front) in preparation for trimming it even.
  20. Use long zigzag to sew top and bottom of stomach/back covering together so it seams like one tube/piece of fabric.
  21. Omit elastic sewn around the bottom of the bikini top in the directions.
  22. Attach stomach/back piece to bikini top piece with right sides together.
  23. Hem bottom with a half inch hem and square zigzag.
  24. Use directions on Papercut’s website to make straps (1 1/2 inch wide cross-cut strips of fabric and 3/8 inch elastic), but use square zigzag for all (width of 4, length of 1.5) rather than the long zigzag.  Also, double sew (sew twice) when sewing right sides of fabric together.
  25. Step 9 in the directions with lots of stitches!!!
  26. Step 10 in the directions with lots of stitches!!!
  27. Test in the shower or at the beach.

Here’s a look at the back and inside of the suit.

Summer=Swimsuits:  Soma Bathing Suit Hack

Summer=Swimsuits:  Soma Bathing Suit Hack

Summer=Swimsuits:  Soma Bathing Suit Hack

Summer=Swimsuits:  Soma Bathing Suit Hack

I tested the suit and the high rise bottoms out on Wednesday for a good couple of hours at a local pond and here are the successes and failures of the suit in its current state.


  1. The general silhouette is great and very flattering.
  2. This works well as a tankini and my version offers good coverage in the stomach area, which I like.
  3. The style lines and color blocking are cool.  I’m happy with how that turned out.
  4. The top gives some support and separation in the chest area.
  5. I finished this crazy suit!

Failures (or at least “Elements I am Not Satisfied With”):

  1. The underwires do not lay flat against my chest.  Since I don’t have any experience making bras at this point, this is something I can’t troubleshoot.
  2. The polylaminate foam I put into the upper and lower cup areas does not offer full coverage.  I cut off the seam allowances and had to stretch the fabric to put them in, so that they seemed like they would offer full coverage, but when I put the suit on, the foam in the bottom cup sinks down and leaves the exact area where I wanted padding unpadded!  I tried to use a zigzag above and below the central seam joining the cups, but my machine, which sews well through all kinds of materials, skipped like crazy and just couldn’t handle sewing right on that foam.  I used a walking foot, wooly nylon in my bobbin and nice Gutermann thread up top, tried both a stretch and a jersey needle (new ones), and messed with the tension and feed-dog pressure.  What the heck?!!

If you look at this picture, you can probably see the holes from one of my topstitching attempts on the lower cup on the right side:

Summer=Swimsuits:  Soma Bathing Suit Hack

Here’s an inside shot, too, for those who might be curious for a close-up:

Summer=Swimsuits:  Soma Bathing Suit Hack

After trying numerous solutions to the foam problem, I knew that I just needed to finish this thing and move on with my life.  I’ve been mulling it over, working on it, and procrastinating on it for so many months now.

My conclusion is that it’s still a wearable suit.  It does offer some support, even if the support isn’t right.  After my trip to the pond, though, I realized that I could live with the underwire situation being imperfect, but I really want to fix that foam.  The foam from the upper cup is partially stabilized by being caught in the fold-over on the top edge but the bottom is not anchored down, just held between the outer and inner fabric.

Readers, what would YOU do about stabilizing the rest of the foam?  Can I use a straight stitch?  I had assumed it needed to be a stretch stitch, but maybe I’m wrong.  Can you troubleshoot this suit for me?  What would you have done differently with the underwires?  Is this pattern one that can even be made into the kind of suit I tried to make it into?

My hope in posting all these details is that someone, somewhere will be able to take my experiment to the next level and perfect it.  I’m also hoping some of you will know what I did wrong and tell me.  Even though I will probably not make this suit again, I want to know how I could have made it better.  When I set out to make this, I scoured the internet to find out if anyone had put in underwires, and couldn’t find that they had.  I’m hoping someone will find my post, and take this pattern/idea one step further.  You can do it!  (But if you do, leave me a link in the comments so I can go and check it out.)

For anyone who’s curious, I got my fabric from Girl Charlee and my elastic and polylaminate foam used for swim cups from Sew Sassy.  The underwires came from an old bra.



4 responses »

  1. I would try the straight stitch! What do you have to lose, really. Did you try tacking it by hand from the inside? You could even do a decorative hand sewn stitch!

    But I love the suit, it looks fantastic. Great color combination! And I LOVE that you were bold enough to try the underwires.


    • Thanks, Christine. I think I was afraid that tacking it on the inside would cause dimples that showed on the outside, so I didn’t end up doing it. Thanks for the ideas and the encouragement. I’m gearing up for another batch of projects and there are a few bathing suits in the bunch. Maybe this will be the year of success! 🙂


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