We’re in the home stretch with our Cottesloe swimsuits, friends! Today we are going to go through the elastic insertion for all views of our swimsuit pattern. And if you are making view A, B, or C, this is actually your last and final step! Woo-hoo!
Like I said, inserting the elastic is the same for all views, but I’ll be showing it to you on View A. I’ll sneak in a few photos of what it looks like on bikini view C, though! And if you’re making the low back View A with ties, make sure you stick around until the end so I can show you how to finish up those ties once the elastic is done.
OK, let’s do it!

Once you’ve cut all of your 1/4″ elastic lengths according to the measurements provided in the CUT section of the instructions (elastic lengths are different for all views, so make sure you cut the right ones), you will need to divide your neckline elastic into sections according to Neckline Allocation measurements in the ELASTIC INSERTION section .
We’re going to use the Front Neckline measurement to do this, and I’ll break down how to below.
Start from one end of your elastic, this end will be your left shoulder. From the Left Shoulder, use your Front Neckline measurement from the chart above to mark the length of your entire front neck – the new mark will be your Right Shoulder.
The length in between your left and right shoulder is your entire front neckline.
Now divide this front neckline in half, marking halfway between the Left Shoulder and Right Shoulder. This is your Center Front.
The remaining section of elastic beyond the Right Shoulder, is your Back Neckline. The opposite end of the elastic will also meet at the Left Shoulder.
Divide the Back Neckline in half, marking halfway between the Right Shoulder and second Left Shoulder. This is your Center Back.
Now mark the centre front and centre back of your neckline on your swimsuit.
Place your swimsuit in front of you with the wrong side facing out (you may or may not have a lining or shelf bra. It’s all treated as one fabric at this point).
On the wrong side if the fabric, Pin the (original) Left shoulder of the elastic to the left shoulder of the swimsuit. Line it right up along the edge of the neckline.
Then pin your center front mark to the center front of your swimsuit.
Continue pinning around the entire neckline, matching up the markings for the right shoulder, center back, and then back to the left shoulder.
Overlap the elastic slightly at the left shoulder.
You can pin the elastic to the swimsuit in a few more spots if it helps keep it in place. Just remember that the elastic will be shorter than the neckline in some spots and will be stretched when pinning and sewing.
Now divide your armhole and leg opening elastics each into equal quarters.
Let’s start with the armholes. Divide the armholes into quarters, as well – the shoulder seam, side seam, and half way between the two on front and back.
On the wrong side of the fabric, start pinning your elastic at the underarm/side seam.
Pin all the way around, matching up the quarter markings, and overlapping slightly at the underarm.
Now also divide your leg openings into quarters – the side seam, crotch seam, and half way between on both front and back.
On the wrong side of the fabric, start pinning your elastic at the side seam.
Pin all the way around, matching up the quarter markings, and overlapping slightly at the side seam.
If you are making a bikini without a waistband/underband, repeat the same process with your waistline and underbust elastics.
Divide the elastics into quarters, and divide the garment edges into quarters.
Pin them in the exact same method, starting at a side seam, matching up the quarter marks, and overlapping slightly.
Time to sew your elastic to your swimsuit with a zig zag stitch. As you sew, the edge of the elastic should line up with the very edge of the fabric.
You will also need to stretch the elastic as you sew so that the elastic and fabric are aligned.
Sew your zig zag stitch directly down the center of the elastic.
Here is how it looks once it is attached.
Now fold the elastic/fabric raw edge towards the inside of the garment. The elastic will be sandwiched in between the fabric now. Pin in place if needed.
From the wrong side, zig zag stitch again. This time right up against the raw edge. Again, stretching as needed as you go. This will enclose the elastic.
You will see two rows of zig zag stitching form the inside, but only one row from the outside.
Repeat the same process for the armholes and leg openings.
And if you are making a bikini with elastic at the waist and underband, repeat the same process there as well.
Alternatively – instead of using a zig zag stitch on the final step (where it is seen from the outside), you could use a twin needle to enclose the elastic. Then you will have two rows of straight stitching from the outside and zig zag along the inside.
You would have to sew this step from the right side of the fabric, though, so make sure you are catching the edge of the elastic on the inside as you go.
// FINISHING VIEW A TIES //
Once all the elastic is done, you can now secure the ties on View A to the back neckline.
Turn your swimsuit inside out with the back facing you.
Lay the ties straight from the side seam to the back neckline. Make sure they are lying straight! Pin to the edge of the back neckline.
Secure by sewing the ties to the back neckline right along the elastic topstitching, again using a zig zag stitch.
Ta-da!
LOOKING FOR MORE COTTESLOE POSTS?
Here’s the full list of Cottesloe posts and tutorials:
- Pattern Tester Round-up
- Inspiration + Ideas
- Where to Find Swimsuit Fabric
- View B Full Suit Construction (+ Optional Lining)
- View A Full Suit Construction with Shelf Bra and Ties
- Views C & D Bikini Construction
- Basic Elastic Insertion for All Views (this post!)
- Waistband and Underband Elastic Insertion for Views C & D
We absolutely love seeing what you make, so don’t forget to tag your creations with #MNcottesloe and @megannielsenpatterns when sharing on social media, and check out what everyone else is up to!
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