The Midline Swimsuit sewing pattern was designed to be customizable to your lovely body and personal preferences. The shelf bra option is simple and a great choice if you want a little additional coverage/support. The swim sports bra pattern has additional support built in and can be left separate or stitched to the suit. The swim sports bra can totally be used with the swim bottoms for a bikini set, or sewn with athletic fabric (non-swimwear) for a supportive sports bra.
Some might call the following sewalong series commentary “painfully lengthy”. I like to think I am being thorough and overly detailed. If you are going to skip ahead at the very least please read page 7 and 8 in the instructions to review sizing + grading before cutting your fabric.
For your convenience the pattern is available in a print at home format with layers (which allows you to choose only the relevant sizes, if desired) as well as a copy shop file to print out or use with a projector.
Sizing + Fit: The swimsuit was designed to meet at your midpoint/waist–but you can have it cropped or longer if desired. The swim top as drafted is snug around your bust (6″ of negative ease) and has zero ease at your waist. The swim bottoms have negative ease at the waist and thighs so they are snug and won’t shift in the water.
If you’d like to have the swim top snug at your waist to keep it from floating in the water, or have your swim sports bra more fitted, it is a very simple grading adjustment. “Grading” may sound intimidating to newer sewists–don’t fret! You’ll have bragging rights, “Oh this swimming suit? Nbd, I just graded between sizes to get a custom fit.”
Guidance on how to easily grade the swim top is found on page 7 of the instruction booklet. For the swim bottoms I encourage you to look at your waist and thigh measurements on the size chart and grade between sizes. Page 8 of the instructions will show you exactly where to make the simple adjustments when grading between sizes.
Throughout the instructions you will see different stitches referenced (standard zig zag, elongated zig zag, etc). On page 4 of the instruction booklet you will see what width and length I use on my machine. All machines are different–your machine may not even have numbers! You have my permission to ballpark your stitch calibrations. Backstitching is expected, but not explicitly stated.
Once you’ve settled on your finalized swim top pattern and support option (if desired) it is time to cut out your fabric! Please note I did not strictly use swim fabric for this sew along sample for visual purposes. It is *really* important you use fabric made for swimwear so you don’t have a saggy swimming suit at the pool.
I recommend waiting to cut any elastic until you reach the step in the pattern. That way you can pin the length needed and try it on that area of your body to make adjustments as needed. It’s much easier to add length here than to unpick layers of double needle stitching on swimwear (ask me how I know).
TIP: Some swim fabric, particularly solid colors, are really hard to tell right from wrong. Right after cutting out I like to chalk some lines on the side seams on the wrong side so I can keep the right/wrong sides consistent while I sew.
OK! Enough one-sided chit chat. Let’s get sewing.
Shelf Bra
If you plan to use foam cups now is the best time to sew them to the shelf bra front. I do not love the rigid swim bra cup options that you typically see at a fabric store. I prefer foam cups you might find in a sports bra. If you don’t have extra lying around they are available to purchase online–search “bra cup inserts” for many options.
The pattern includes a bust point as a starting reference, but it is always great to hold the piece up to yourself and make needed adjustments. I have not photographed the steps for this sample. There are some great videos demonstrating different tips on how to sew on the cups – the swimmer queen Katie Makes A Dress has a really helpful video on sewing swim cups to your lining.
As written the right side of the lining and optional cups will be against your skin – but this can be reversed if that is your preference.
The next step is to add some additional shaping for your shelf bra. I like including the shaping to help avoid the dreaded uni-boob you hear about when sewists tell scary stories around the campfire. Mark a line down the center front, and then additional markings 3″ down from the center front neckline and 1″ from the center front bottom.
Place your narrow (1/4″ or 3/8″) elastic on the top of the line you just marked and with a standard zig zag stitch make two stitches, back stitch and stop with your needle down. Hold the fabric firmly from behind and pull the elastic as tight as you can. Pull from behind while you proceed stitching and stop 1″ from the bottom and back stitch. Trim the elastic.
Next place the front and back shelf bra pieces together matching up the side seams, wrong sides together. I like enclosed seams as much as possible! Sew a standard zig zag stitch with a narrow 1/4″ seam allowance.
Trim about an 1/8″ off the finished side seam allowances. Flip inside out and finger press the side seams and pin side seams together again, this time with right sides together. Also, now pin the shoulder seams right sides together. Sew a standard zig zag stitch at 1/2″ seam allowance. Trim shoulder seam allowance 1/4″ to reduce bulk later in the construction.
Now we will work on the shelf bra band. Consult the elastic length recommendation for the 1.5″ under bust elastic on page 5. Pin this length around your under bust area and decide if you need to make any adjustments. You will overlap the elastic by 1/2″, so keep that in mind. Once you have a snug but comfortable length go ahead and cut the elastic.
Now you can either use the raw band or cover it. If you wish to cover the under bust band you will need a strip of swim fabric (lining or main fabric) that is 2x as wide as your elastic (3″ if using 1.5″ elastic) and as long as the under bust elastic.
Overlap the elastic by 1/2″ and stitch in place (any stitch your heart desires) to form your loop. For the band match right sides together and sew with a straight stitch a 1″ seam allowance.
Wrap the band around the elastic loop with right sides facing out. Pin like crazy keeping the band as even around the top of the elastic. The high volume of pins will save you annoyance while sewing.
Sew an elongated zig zag stitch around the edge of the band to secure layers together. Double check that you caught the fabric on both sides – quickly zig zag any offending areas that escaped the first pass around.
Take the shelf bra hemline and mark the 1/2, 1/4, and 1/8th points with pins. Do the same for the under bust band.
If you are unsure how to do this I have a Midline Swimsuit Instagram highlight reel that includes a classy video demonstration on dividing an area to evenly space elastic and fabric.
Match up the pins in both pieces and pin together. I prefer to add additional pins in between to make it easier to manage while I sew. Use an elongated zig zag stitch at 1/4″ seam allowance. It helps to hold the fabric behind the machine while you pull from the front, stretching the elastic to be flat with the shelf bra fabric as you sew.
Your shelf bra is done. This was the hardest part. Yay for getting that out of the way! Now you are ready to construct the swim top. Instructions to follow in part 3 of the Midline Swimsuit sewing pattern sewalong (not yet available).
If you would like to share your progress or final make on Instagram: #midlineswimsuit #ginghamhivepatterns @ginghamhive
Midline Sewalong:
- Intro + Swim Top Support – Shelf Bra (you are here!)
- Swim Top Support – Sports Bra
- Swim Top
- Swim Bottoms
