Guide to Sewing Swimwear Part 2: Bikini Top

trash to couture swimsuit

For Part 1: Sewing Swimwear and the bikini bottom tutorial head there first. That post covers fabric, machine set up, tips, drafting a pattern, cutting, and all the details you need to know for Sewing Swimwear.  For this post we are going over sewing the bikini top using COATS Eloflex Thread that is designed to stretch with the fabric. It’s a great thread to use for swimwear, fitness wear, and knits ensuring the seams and hems can expand without breaking the thread. I wanted a basic halter style suit because  I’m a mom of 3 insanely active boys. I’m usually running around the beach or splashing in the pool rather than lounging if you know what I mean. I need a swim top that has support, comfort, and coverage. So I made my own and tested it out during our weekend beach trip and I couldn’t of been happier. 

Get the details below on how to make your own swimwear.



Draft and cut your pattern out. I’m doing a simple halter top. I used a halter suit I already had to draft onto pattern paper (I used parchment paper) and added side panels as well. 

All the pieces cut out using a rotary cutter and mat. 

Sew or serge the side panels on both the front and liner. When using COATS Eloflex thread it isn’t necessary to use a zigzag stitch. I used a standard straight stitch and ball point needle. 

Place front and back WRONG sides together and pin. This is a good time to insert cups if you plan to use them.

I added them and tacked them down on the back/liner with a hand stitch so they didn’t move.

Sew front and liner together. 

I then serged everything together after sewing to clean up the edges.

It will look like this.

Fold-Over Elastic as binding:

To give the suit more support I used Fold-Over elastic (FOE) as binding around the sides and bottom edge. You can also use the elastic method I shared on the bottoms in Part 1.

Measure the arm opening and cut your elastic 1″ smaller.  The general rule is the FOE should be shorter than the opening. I usually do my elastic on curved edges about 80% smaller than the garment measurement. On straight edges I may do 95% or none at all if their is already negative ease.

For the bottom edge I cut 1/2″ smaller and again I made this part just slightly smaller because it’s a straight edge. You will have to adjust and test things when it comes to your garment which is part of the process.

TipIf you do plan to use FOE make sure to add that into the pattern. For example you may want to remove 1/4″-1/2″ from the pattern edge to account for it. 

You will need to evenly distribute the elastic. Measure and mark off the quarters on the garment and the elastic. Pin the FOE encasing the raw edge matching the quarter marks together. You will need to stretch the elastic to match with the garment marks since the elastic should be slightly smaller. 

Sew the FOE to the sides and bottom edge…You can use a standard straight stitch or I like to use a slight zigzag (2.5) making sure to encase the front and back of the FOE.

Tip: When sewing elastic edges, pull the elastic with minimal tension on straight edges and about 60-70% on curved edges. 

Top Strap:

Again using FOE. Cut a large amount of FOE as you will be using this to criss cross in the back and tie into a bow. Mine measured _. Fold the strip in half to get midpoint and pin at midpoint of neckline. Start sewing (zigzag 2.5) at one side of the neckline pulling just slighty. Once you reach the end of the neckline continue to sew along the edge of the FOE strip (without pulling at this point). Sew all the way down till the edge. You will want to fold the bottom edges inside to give those a clean finish as well. Then go back up to the other FOE strip and repeat for the other side. 

Lastly, fold over the side edges 3/4″ and sew along the raw edge to create a casing for the back strap. 

Cross the straps, pull through the side casings (with a safety pin or loop turner), and tie!



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