Start Collection
a series bulbs on soil with one in focus growing a tree inside

Complete guide to the design and manufacture of plus size swimwear

a plus size woman looking to the distance in a swimsuit


While body positivity in fashion is more pronounced than ever, brands are not immune to criticism from the plus-size community.

Some so called plus size swimwear manufacturers and brands tend to produce and offer a few pieces of the same design in bigger sizes with a pretty plus-size-inclusive marketing campaign but that does not do justice to the struggles curvy women experience.

If you’re considering bringing a plus size swimsuits to market, it would be a gross understatement to say that your approach should be vastly different.

Plus size women go through different pain points and the entire process from design to manufacturing should be as unique as the women who will don your plus size bathing suits.

If you’re in the market to design some stellar plus size swimsuits for women, you’ll find yourself knee-deep in a lot of planning. Truth be told, as plus size swimwear manufacturers ourselves, you’re doing it right if your pre-planning stage is significantly more laborious.

From the design to the technical construction itself, each step requires a wealth of planning. So, if you’re here to build a sustainable, honest and comprehensive plus size bikini and swimwear line, here’s a one-stop guide to everything you need to know.


XL swimwear – Flesh out the problems

Before you jump to the drawing board, get at the heart of your target market’s pain points. We’ve scoured around doing interviews and research to find out some common problems to help you get started.


1. Who is a plus size swimwear consumer?

Plus size includes a huge array of women and adding a few XL, XXL and XXXL sizing to your line does not classify as plus-size inclusive.

Ask yourself, what sizes fall under the “plus-size” umbrella and what size range will your line cater to? You’ll be hard-pressed to find a universal plus-sizing chart but Plus Model Magazine gives a good estimate to use as a base

    • Plus size: 10-14 (US)
    • Supersize: 1X-6X
    • Extend size: 7X and up

It’s safe to say the term “plus size” is not inclusive of everyone either. However, for the sake of making this easy to digest, sizing 10 and above will be classified as plus size in this article.

But do keep in mind the differences as you start sketching out your line and use a size chart to better gauge your range and what sizes you’d like to include. Remember, a design fitting a size 10 consumer may have to look different to an X7 consumer (you’ll know why below).


2. Trendy plus size swimsuits – style options

few plus size women in swimsuits enjoying the pool


At the epicenter of plus size women’s fashion problem lies the whole style debacle. It’s sad but it’s reality nonetheless that curvy women have a limited option when it comes to stylish plus swimwear.

We’re not here to throw shade at any brand, but wearing a swimsuit and going to the beach or pool is a fun activity.

There’s a common misconception that plus-size women look at plus-size beachwear with the purpose of covering themselves up as opposed to celebrating their bodies.

We’re here to stamp that bug to death because plus size women love to celebrate their beauty just as everyone else. So, why are we midway into 2019 thinking curvy women like the 1900-show-only-your-ankle-look?

With that in mind, think about providing the coverage, support and comfort without compromising on style.


3. There is no such thing as one size fits all for plus size swimsuits for women

As with the sizing debacle, don’t use one fit model to gauge the sizing for the rest of your plus size bathers range. Most popular brands use an hour-glass figured model to shape their range.

Just like with a traditional sizing range, use a variety of silhouettes to see how your swimwear will look on your target market. That should be the premise of how you reshape and tweak your samples into a final product.

Now that we’ve nailed down a few common problem areas in swimsuits for plus size women, let’s get to the meat of it: how can you ensure your plus size swimwear line is as stellar to your consumer as it is to you?

Answering this question is a two-fold process. One requires some digging into design elements and the second focuses on the technical construction of your swimwear.


Design elements

When you’re procuring the perfect swimwear range for plus size women, a few important design factors need to be considered.

Although each style is unique and would require different design features, a few common themes run across most (if not all) plus size swimwear.


Style, coverage and support – Whether it is a plus size one piece swimsuit or plus size bikini, l these three elements are crucial to nail when you’re designing your swimwear range.

For example, straps of a swimsuit will provide the most support. Some designs may look cute with a thin barely-there strap. But for the most part, bustier women need support from the straps to hold the silhouette as well as to avoid any unruly bulges.

You want a swimsuit that sells and not one that only looks cute on the mannequin! As with the straps, pay attention to your back design.

Although plus size women love to bring sexy back (get it?), anything unflattering will leave all that back in the early 2000’s just like Justin Timberlake’s frosted hair tips.

Lastly, a cheeky cut may be all the rage now, but consider if your target market would prefer a little more butt coverage and design a back cut accordingly.


Use stylistic features to give a leaner frame –  All women’s bodies should be celebrated. But it doesn’t hurt to play with the illusion of design to give your consumer a smaller frame. Use color blocking style or trims down the waist and sides to give a thinner waist or a longer torso.

Focus on a cut that shows off the wearers long legs. Either way, use designs to your advantage to not only make some pretty stellar looking pieces of swimwear but to also provide some fringe benefits!


Skip the embellishments – Although it’s tempting to add frills, buckles and the lot, try to forgo them. The bulkier the swimsuit, the less attractive it can be. Sometimes a classic silhouette goes a long way.

If you wish to use them, strategically choose how and where you want to use the embellishments and make sure it adds to the value and not detract from the wearer’s look and feel.


Scraping the deep cuts – 2018 and 2019 saw the rise of the deep v neck cuts (front and back, up and bottom). But keep in mind the silhouette of your wearer. Less bustier women may be comfortable enough to pull it off but plus size women require designs that cater to their bodies.

We are all here to celebrate and support whatever women choose to wear.

However, a common pain point many plus size women face is the lack of fabric in a piece of swimwear that is designed for aesthetic purposes and not realistic goals.

You will also find some useful tips in our full guide on how to design swimwear that can be manufactured.


Technical construction

Once you’ve crossed your T’s and dotted your I’s with your design, it’s time to drill down the technical construction.

To bring your plus size swimwear to life, you have to be realistic and consider the technical elements that go into the production of a supportive garment.


One vs. many panels – Swimwear designed with a traditional sizing set is most often sewn with one panel covering the entirety of the front and one at the back.

When designing a plus size swimwear, approach the paneling with a different perspective and test out using a few panels. To ensure optimal fit, coverage and support, using multiple panels can help achieve a seamless look to the garment in addition to reducing wastage, as well.


Double the support – Let’s be real.

You can’t get away with plus size swimwear without doubling up the lining around the chest area. This is a non-negotiable in providing adequate bust support.

Double up the lining and even sew in an inner bra. If you want to go one step further, adding an underwire can massively support bustier silhouettes. Having an actual bra sewn into the swimwear might seem strange to our fellow ABC sisters.

But for all other women who fall into rest of the alphabet with their breasts, an actual bra can help keep everyone in place. Yes, you can even stretch this into a bra with clasps at the back and all the works.

Trust us, women will appreciate it. Win-win, baby.


Silicon , Use it – Silicon is every close-to-skin garment makers dream. Got a strapless bra? Add in a silicon line around the edges to keep it in place. Similarly, adding silicon lined support across the swim garment can help keep it in place.

The silicon gripping can help ensure coverage without anything spilling out of place. Keep in mind how you can leverage this and add it to your final garment as you run through your CADs.

Silicon is not only used as a gripper but can also be used in the printing of the design.


Stabilizers are a must – Don’t skimp on the stabilizers.

Stabilizers are material that you add to the garment to hold the piece in place. It prevents fabric stretching so that the garment holds to the silhouette as it was designed to.

Stabilizers are most commonly inserted at the back of the inner bra (also called the wings) and the front of the bar (the cradle) so that you’re optimizing the fit to the wearer.

When you’re avoiding fabric flexibility and looking for the stability of the piece, stabilizers such as nylon mesh will be your best friend.

Lining fabric that is most often used as stabilizers is measured in deniers. This is the weave density of the lining you would choose to add.

You can choose a combination or stick to a certain type of stabilizer depending on your preference and style.


Manufacturers, choose them wisely – When you’re sourcing for plus size swimwear manufacturers, the first no-brainer is going with a manufacturer, who has previously worked with plus-size garment production.

Giving the job to a manufacturer, who has had no experience with plus size production will leave you wanting to tear your hair out. Seasoned plus size swimwear manufacturers can really help bring to life your swimwear and understand the technical demands required.

Similarly, opt for a cut and sew technique to stitch up your panels. This will allow different pieces of your swim garment to hold together.

Check out our full guide on selecting the right manufacturer to help you out more in this regard.



Deciding to embark on producing a plus size swimwear line is tough work but the truth is, the pay off is certainly worth it.

If you take the time to nail down design without compromising fit, support and coverage and the technical construction, you’ll be as excited as the Aussie’s were during the gold rush.

The planning stage will take longer than the conventional style strategy stage. But know that your designs have the power to change the perception of plus size swimwear.

It’s time to say goodbye to unappealing designs and hello to sexy and cheeky featuring support and coverage.



So are you looking to design and manufacture your own plus size swimwear line?

Talk to the experts at Runway Kit and see how they can help. So, drop us a line and let’s grab some coffee. From ideation to execution, we will provide everything you need. We’re here and coffee’s on us.

P.S. The views from our office aren’t too bad either.



Runway Kit offers fashion designers and entrepreneurs the option to design, sample and manufacture in smaller, flexible quantities – all at start-up friendly, transparent costs.

Subscribe below to our newsletter to receive the latest updates on our blog.

Join the Runway Kit community

Sign up for latest offers, catalogs, news and more.