Swimsuit Sewbration

How to Sew a Swimsuit — Adding Elastic — Swimsuit Sewbration Sewalong Day 5


Today in our swimsuit making journey, we are going to walk through the steps of inserting the elastic. This is usually the most tricky step for people but with some practice it does get easier! If you start getting frustrated pull out some scrap fabric and practice a few more times before you do the final project. And even then you can always unpick elastic and reinsert it! 
Almost all raw edges of a swimsuit will be finished off with elastic. This will help hold the swimsuit to your body instead of sagging in the water. I suggest putting the elastic in the top of your swimsuit first. This will help you get a feel for how to hold the elastic and stretch it while your sewing.

The pattern will tell you have much elastic you need to cut out for each section. You should have one for each arm hole, one for the front neckline and one for the back neckline. These last two are sometimes combined. I like when they are separate because then you aren’t dealing with such a big space. I have also found that it is easier to NOT make your elastic into a loop. Usually you would layer the two ends of the elastic and sew them together creating a loop but I have found it can be tricky to keep the elastic from twisting and having an equal amount of stretch while sewing it in. 
For myself, sewing the cotton elastic in is a lot easier than sewing in the clear elastic, but like I said before, with practice it gets easier so you just need to have patience during this step. I have also found that I like the feel of the clear elastic against my skin much more. But you can use whatever you like most, just make sure you are using swimwear elastic. 


I first start by marking the elastic and the armhole into fourths. I am then place the elastic up against the edge of the arm hole on the wrong side, or the lining side of the swimsuit. I match up my markings on the elastic to the markings on the suit so that the stretch will be evenly divided. Then I can start sewing the elastic in place. I always use a zig zag stitch that is similar in width to my elastic without going over or a serger for this step. I stretch each divided section of elastic to equal the fabric.
After the elastic is sewn in I turn the edge over so that the elastic is hidden and topstitch it in place. I will use either a zig zag stitch or a double needle for this step. The double needle always looks very professional, if you have a cover stitch machine this would be the perfect time to use it!


I do these exact steps for the other arm hole and the back neckline, but I like to leave the front neckline open and put bra cups in before I add the elastic. In tomorrow’s post I will be talking all about adding bra cups to your suit. Once they are in I finish off the front neckline with those same steps. If the front and back necklines are split between two elastic pieces I will only divide that up into two sections so that the stretch is evenly placed. 

Once the top of the suit is complete I add the elastic to the legs. This is where I do it a little differently than some patterns suggest. I feel that everyone is so different in their legs and butt that it can’t and shouldn’t be the same for everyone. So instead of using the measurement that is given in the pattern I like to measure myself and see how I would like it to fit. Obviously you can’t do this if you are making the suit for someone and can’t get their measurement, in that case you should just use the patterns recommendation. But if it’s for yourself, measure it out! Wrap the elastic around your leg and butt, put it where it would sit in a swimsuit and see what works for you. I suggest going a little tighter than you think because it will stretch out with time, but obviously don’t be cutting off blood circulation! 


Once you have your piece of elastic you can line it up with the wrong side of your suit, on the edge, and get ready to sew. I also do this part a little differently than some patterns suggest. Instead of dividing the leg hole into four equal sections you should be stretching more over where it will fit on your butt and less over where it lays on your groin. You need more coverage and tightness in the back than you do the front! A tight swimsuit in the groin is awful so this is where you con completely make it how you want it! You still want complete coverage so you should still be stretching the elastic but it’s nice to customize exactly where you want it! 


This is a good place to practice. I suggest even basting the elastic in first to see if you like the fit and then doing a more permanent stitch once you have tried it on. After you have put the elastic in to your liking then you can fold the edge over and topstitch the elastic down, like we did on the top. After that you may be adding elastic to the waistband, which is done just like how we did the armholes and neckline! 


Whew. A LOT. I know. It seems harder than it really is. And practicing will help a lot! The more swimsuits you make the better you get at putting elastic in, I promise! Tomorrow is all about adding bra cups! Can you see how close we are? SO CLOSE! You can do it! Happy Sewing Friend! 

2 Comments

  • Stephanie Mayes

    I love how you didn’t settle for whatever bathing suit you can find. Honestly I still haven’t found a bathing suit I’m comfortable in after a year of having my 2nd child. Thanks for sharing your techniques! You are one talented momma! ❤️