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Introducing the Cottesloe Swimsuit!

Cottesloe View A with tie studio shot

The classic swimsuit set

The story of the Cottesloe swimsuit began almost two years ago when summer was coming and I needed a new swimsuit. After a few dressing room disasters, I was feeling pretty upset about the ready to wear swim I could find. I was really dissatisfied with the fit of all the full suits, and none of the bikinis had good coverage or seemed sturdy enough to withstand being in a pool with three kids grabbing at you all the time. I wanted something classic with wide shoulder straps and sleek lines. Something that was more athletic. And something that had good coverage. Introducing the Cottesloe swimsuit pattern!

I’ve spent a lot of time developing this pattern and tweaking the fit and variations over and over again. I really wanted to get it just right. After wearing my personal makes for two summers I’m incredibly happy with how my Cottesloe swimsuits have performed and held up. I finally feel comfortable in a bikini again. The more I worked on it the more excited I got about the variation potential, so we adjusted a lot of the details to make this pattern incredibly easy to hack and make your own. Consider it your swim block to help you bring your dream swimsuit ideas to life!

Cottesloe view D studio shot

Details details details

As you know I love providing you with lots of value in my patterns, so I have designed this pattern to be modular. A lot of the views share pattern pieces and we’ve even added in a bonus pattern piece for even more options. Though we’ve set out some views to show you how you can use this pattern, please don’t be limited! Mix and match your pattern pieces to make your own combinations! I’d love to try making a full suit that uses the back bikini top and bottoms rather than the one-piece back. Wouldn’t that be cool?

You can make this pattern in a variety of different swim fabrics as long as they have at least 50% stretch. This pattern is designed with a lot of negative ease so you need to make sure you check the stretch percentage before sewing. The good news is I haven’t yet purchased a swim fabric that didn’t stretch at least 50%. Swim fabrics can vary in composition, and they do have performance differences. You can make this swimsuit from any swim fabric and any swim elastic – you can even get away with regular elastic if you’re more of an intermittent or seasonal swimmer. We provide a lot of detailed information in the pattern instructions on which fabrics and elastics are best and which to use for which situation.

I’ve worked really hard to simplify the swimsuit sewing process so that this is a perfect introduction to sewing swimwear. There isn’t anything complicated here and everything is achievable on a regular sewing machine. You’ll be shocked by how easy it is to sew your own swimwear!

You can do so much with this pattern it’s crazy. By changing your fabric choice you can even use it to sew your own sports bras, underwear and even leotards.

How does it fit?

Cottesloe has a very close fit. As it’s a swimsuit it is designed with negative ease so the finished garment measurements will be significantly smaller than your body. Don’t let this scare you. Swimsuits need to fit very close to your body so that they stay in place in the water. The coverage around your seat and crotch is generous so that you can feel comfortable moving around all the time, as is the coverage around the bust and underarm. I’ve done everything in these swimsuits from swimming laps to just splashing around with the kids, and lying on a towel reading a book – and honestly, these swimsuits have been perfect for each situation.

The fit of the Curve swimsuit is more generous in the bust than the standard swimsuit, so keep that in mind if choosing between the two ranges if you’re between a 14-20. In addition to more ease in the bust, it also provides more bust coverage and the shoulder straps and back ties are wider for more support. The standard swimsuit is drafted for B cups (though honestly, you can get away with more due to stretch) and the curve swimsuit is drafted for D cups and above. As a guide Sammy (brunette with a bob) wears a size 6 and is a B cup, Mykeesha (curly hair) wears a size 10 and is a C cup, and Steph (our gorgeous curvy blonde) wears a size 22 and is a G cup.

Megan Nielsen Cottesloe Swimsuit View A // Sizes 0-20 MN2501-View-A-with-tie studio shotView A with tie studio shotIntroducing Megan Nielsen Cottesloe Curve swimsuit // sizes 14-30Introducing Megan Nielsen Cottesloe Curve swimsuit // sizes 14-30Megan Nielsen Cottesloe Swimsuit View A // Sizes 0-20

View A one piece swimsuit with scoop back

View A has been thoughtfully designed to provide you with all the benefits of a full suit whilst still being incredibly pretty and supportive around the bust.

This view includes a beautiful low back that is just the right depth and a shelf bra that is cleverly supported by back ties that are anchored to the shelf bra at the side seams. You can easily adjust the amount of support your shelf bra provides by tightening or loosening your back ties. If you want the same bust support without a bow, you can easily shorten these ties and sew a hook closure with a G hook – or you could even simply anchor a single strap from one side of the suit to the other. I’ve tried to make it as easy as possible to adjust any detail you’d like.

You can also easily sew bra cups into your shelf bra and fully line your suit and we’ve provided instructions in the pattern to help you do that.

If you don’t feel you need bust support you can also leave the back ties and/or shelf bra off this suit and rock a stunning low back one-piece. As someone with a small bust, this is what I have done with one of my suits and I really enjoy the bare low back.

Megan Nielsen Cottesloe Swimsuit View B // Sizes 0-20
MN2501-View-B-1 Studio Shot

View B is a one piece swimsuit with high scoop back

This is your classic one-piece swimsuit with a high scoop back. This suit is wonderful if you want more back coverage or are looking for a more athletic full suit. This view is my favourite swimsuit for swimming laps. It’s also the fastest view to make out of all four.

Because the back extends further up you’ll find that this swimsuit fits more closely than View A around the chest. Though this view doesn’t technically include the shelf bra you can definitely include one as the pattern pieces are designed to be modular.

MN2501-View-C Studio Shot
MN2501-View-C Studio Shot

View C is a bikini top and a low rise bikini bottom

This bikini includes a low rise bikini bottom and though the bikini top has the same fit as View D it provides a little less coverage and support under the bust than View D. This is a great bikini for anyone who prefers a low rise bottom and isn’t a fan of wide waistbands. We worked hard to make sure that although this bottom is low rise it is still comfortable and provides enough coverage.

The View C bikini top is quite narrow at the centre back and this is drafted intentionally so that you can easily add a centre back G hook closure if you would prefer. It’s a simple addition once you have finished sewing up your suit.

Though this view doesn’t technically include wide waistbands we have included a bonus pattern piece for the bikini bottoms if you want a low rise bikini that includes a wide waistband. A lot of the details of this view are thanks to suggestions from our wonderful pattern testers and are a fantastic example of how important testing is.

MN2501-View-D-studio shot
Introducing Megan Nielsen Cottesloe Curve swimsuit // sizes 14-30
Introducing Megan Nielsen Cottesloe Curve swimsuit // sizes 14-30

View D is an athletic inspired bikini top and high waisted bikini bottom with wide waistband

This view is my dream bikini! The bikini top includes a separate wide underbust band which provides additional support and makes it possible to use this bikini top as a sports bra. I have two sports bras made from this pattern and they are my absolute favourite. The separate underbust band also provides more variation potential as you can cut it from a contrast fabric for visual interest and use the seam to add details.

The bikini bottoms are high waisted and include a separate wide waistband like the bikini top. This wide waistband again makes for an athletic look and provides additional support, as well as making it easier to personalise your suit. You can cut your waistband from a contrast fabric or insert details into the seam such as ruffles or a peplum skirt.

My View D bikini is the only bikini I have been able to swim laps in and still feel like it’s staying put, and it’s due to the support provided by those wide underbust and waistbands.

If you like high waisted bottoms but don’t want the wide waistband, you can still sew the high waisted bikini bottoms without the wide waistband! The black/marble bikini that Mykeesha is wearing below is an example of that. For that bikini, we omitted the wide waistband and finished the waist edge the same way as for View C.

The options are really endless!

Megan Nielsen Cottesloe Swimsuit View D // Sizes 0-20

All the sizes!

I’m so happy that Cottesloe is available in my entire extended size range! Sizes 0-20 are available in printed and PDF format and Cottesloe Curve sizes 14-30 are available in PDF format.


We will be posting a full sewalong for Cottesloe a week from now! There are a lot of fun details included in this pattern and we’ll walk you through how to sew them all and hold your hand for all the tricky bits.

This pattern was so fun to design and I hope you love it as much as I enjoyed working on it for you!

If you have any questions at all please let me know in the comments below or send us an email at

We’d love to see what you make with the new Cottesloe and Cottesloe Curve pattern! Don’t forget to tag your creations #MNcottesloe and @megannielsenpatterns to share what you’ve been working on, and check out what everyone else is up to!


Here’s the full list of Cottesloe posts and tutorials:

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!

Don’t have the Cottesloe pattern yet?

Don't have the Cottesloe pattern yet?

Order Cottesloe today in sizes 0-20 and Curve sizes 14-30

About Author

Anita is the Operations Manager here at Megan Nielsen Patterns, and happily works on multiple areas of the business in any one day! Anita is the first port of call for any of your customer service enquiries, manages daily operations and oversees all pattern production, graphic design, website maintenance, inventory management & drinking all the coffee/eating all the cookies in the cupboard.

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5 years ago

Hi there,
So pleased to see a swimsuit by Megan Nielsen patterns! I have a technical question: I love only shorts-style bottoms both for one-piece and 2-pieces swimsuits (but fitted close on the body of course!). This kind of bottoms suits my body better, and I love the 50′ vibes of it… Is it possible to alter the bottom of this pattern to have such a result ?
Thank you, your work is amazing!

Louise Walsh
Louise Walsh
5 years ago
Reply to  Lydie

Hello Lydie,
This is exactly what I was thinking. The reason I prefer swim-shorts is to avoid chafing between the legs. Not all of us have an air-gap there! Shorts are a little more modest too. As we age, not all of us want to flaunt our assets.

Gilam Sheikh
Gilam Sheikh
4 years ago


3 years ago

This is such a great swimsuit. I am wondering what you would recommend for me – I wear a 10AU for most clothing but my cup size is DD. Thanks!

1 year ago

Hi, how straightforward is fitting the Cottesloe bikini? I really want to make it but I’ve never attempted swimwear before. I’d say I’m an advanced beginner in sewing. I’ve been sewing for a few years but only a handful of items a year. I can’t find anything in the shops and the cottesloe is my ideal style. Thank you :)

1 year ago
Reply to  Sophie

Hi Sophie! It’s not too tricky – given it’s so stretchy there is a lot of room for error and it’s very forgiving. Most people simply size up or down if needed.

Just remember that your fabric choice can great impact fit. Some fabrics will fit looser than others, so try testing it on fabric as similar to your final fabric as possible. If you decide to fully line your suit i recommend sizing up.

hope that helps!