Adding Support to your Swimsuit

Today, we have another special guest. You might have heard me talk about a bra construction book and how awesome it is…well, we’ve got Norma Loehr, author of Demystifying Bra Fitting and Construction and owner of Orange Lingerie. I started tweeting about my fear of making a bra and it was Norma who talked me down from my fear tree. I hope she has the same effect on you. Below, Norma shows us how to insert an underwire bra into a swimsuit! Yes, she does! For fitting advice, do check out her book. It’s worth every penny. Take it away, Norma.

By this point in the Swim-Along you already know a lot about making swimsuits. Perhaps now you are starting to wonder about how to go about adding some extra support to your suit. While there are several ways to add interior support to swimwear, in this post I will cover the easiest way I know of to add full support to a classic tank style swimsuit. This method allows you to add an interior bra even after the swimsuit is complete.

Quite simply, you will make a bra omitting the back band and then attach it to the side and shoulder seams of the lined swimsuit. As long as your swimsuit has a mid back closure (or a mid back rise) and an underarm high enough to go over the bra frame, this kind of structure will give you the full support you get from your everyday bra.

I am going to focus on where the internal swimsuit bra differs from a regular bra. For more detailed information on bra fitting and construction please refer to my book Demystifying Bra Fitting and Construction.

Let’s start by reviewing the materials needed to create this simple interior support structure. First you will need a full frame bra pattern that has side seams and that fits you well. If you need to find a pattern, feel free to check out my list of bra making resources. When selecting a bra pattern be sure to consider the cup style lines to insure that the the bra cups will be covered by the swimsuit.

In terms of fabrication, for the bra cups you will use poly laminate foam, also called tricot bonded poly filler. This material is only ⅛” thick so it will not add much to the bust line while providing support and smooth shaping. For the bridge and frame of the bra, use a fabric that has little to no movement. This same fabric can also be used for the straps to keep the bra in a stable horizontal position on the body.

Turning to notions, while I used lingerie elastic for this sample, your choice of elastic is tied to how you plan to use and care for your suit. I also used plush underwire casing here but for a suit you will actually swim in consider using an acetate tricot casing instead since it has a lower profile, especially when used in conjunction with foam cups. For full support you will also need underwires and for swimwear I recommend they be nylon coated.

Before you start making the bra, you will need to make a few simple changes to your bra pattern. The first change is to remove the interior seam allowances from the cups so the cups can be constructed without folding the foam since folded foam equals unwanted bulk. The underarm and upper cup allowances for elastic are also removed for the same reason. Do keep the seam allowance at the wire line of the cup to attach the cups to the frame. Below the revised pattern pieces are shown in green on top of the original pattern pieces.

A final pattern change is to reduce the elastic allowance for the upper edges of the frame to ¼” since you only need to fold back and stitch these areas with stabilizer to finish them.

For ½” wide straps – the width that worked best for this cup size and swimsuit – I cut strips of fabric 2” wide (2 x ½” for the straps + 2 x ½” for the seam allowances) by 10” long . These front straps are longer than usual to make it easier to fit the to the body in the swimsuit as a final step.

Cut the pattern pieces as usual. I recommend tracing the pattern pieces onto the foam and fabric and cutting out the pieces with shears for accuracy.

To sew the foam cups together, butt the edges of the cup pieces together and stitch using a 2.0mm stitch length and 4.0mm wide zigzag stitch to securely join the foam pieces together. As you can see from the image below, the cup will curve up behind the needle as you sew the pieces together.

To complete the cups, overlock the upper cup and underarm areas to finish the edges.

You will need to finish the upper edges of the frame before attaching the cups by folding back ¼” fabric over a ¼” strip of stabilizer and zigzag stitching to secure. You can also attach the band elastic to the bottom edge of the frame before attaching the cups. I find that when working with foam, it is easier to do this before the cups are attached to the frame.

Complete bra construction by sewing the cups into the frame, attaching the underwire casing, inserting the underwires, sealing the casing closed and attaching the straps.

As you may have figured out by now, making an interior bra for a swimsuit is a lot less work than making a regular bra! You are now ready to add the bra to the swimsuit by overlocking or zigzag stitching it to the side seams of the suit at the bust line.

To fit the straps, try on the swimsuit. You want the straps to be snug against the body but no overly tight. Pin the straps in place using a safety pin. Once you have removed the swimsuit you can attach the straps as you pinned them by stitching in the ditch of the shoulder seam and then trimming any excess bra strap.

There you have it – the simplest way to add full support to the classic tank swimsuit! You now have a supportive bra inside your swimsuit! If you have any questions feel free to contact me!

Thank you so much for the great tutorial, Norma!

Please do feel free to contact her. She’s very approachable and helpful. So, any of you adding an underwire bra besides me? This would be a great way to take a stab at lingerie, don’t you think?

27 thoughts on “Adding Support to your Swimsuit

  1. Tia Dia says:

    a.m.a.z.i.n.g. I needed this post! I’m not sewing with you on the swim-a-long (too many other things in my life to sew right now) but I have two very beautiful Gottex swimsuits that I love, but they don’t have enough support for me. And this post perfectly answers the conundrum of putting the extra support in. Thank you!!! 🙂

  2. Gjeometry says:

    Very helpful! I’m not going to add support to mine, but if i chose to in a future one, I’ll know how. I’m just trying to get the elastic to lie flat!!

  3. leuinda says:

    Oh my goodness. I don’t know whether to jump up and down with joy or cry. This is great information. I have been struggling / crying / fighting to make an underwire bra inside a suit for the last month so I am *thrilled* beyond belief to come across this info. I had debated over buying the Orange Lingerie book since I have another very complete bra-making book, but I’m buying it just out of gratitude!
    Of course I could also cry because my various apps should have told me about this post last week instead of letting me stumble across it today, now that I’ve been defeated by my efforts and a week away from my family trip. *sigh* Timing is everything.

    • Leila says:

      I’m so glad you found this post. I don’t think it’s a waste of time or money to read all the bra making books. But that’s what I like to do. 🙂 You’re awesome for buying Norma’s book, too.

  4. Jo says:

    Hi Leila,

    It’s an old post but I hope you don’t mind a question! I’m making my first bombshell now and was wondering – did you attach your bra between the lining and the outer layer, or have it ‘hanging’ inside the lining? I’ve got my old bra ready to be repurposed, I just can’t quite figure out the best way to go about it…. Also, did you just cut the straps off and use the bombshell halter straps?? So many new things in this project!

    Anyway, thank you – the swimalong posts from last year are a great resource!


    • Leila says:

      I think it disappeared because I had to approve your comment.

      So yeah, I left it hanging at the underwire part and cut the bra straps off and stitched the top of the bra- where the strap would be along with the halter straps.

  5. Nycki says:

    Thank you, thank you, thank you! I can not find cute plus size swimwear with an underwire (that isn’t completely hideous). Thank you for saving the day!

  6. marlo says:

    And now you’re still helping people 4 years later!
    Seriously–I had almost given up on a completely cute suit that lacked support when I ran across this. New life for that almost-discarded bra and saggy-suit solution, all in one!

Leave a Reply to Pella Cancel reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s