Skip to content

The Week of Swim Suits Grand Finale: Kwik Sew 3780

Due to my computer problems I’m posting totally unphotoshopped (and with wet hair and no makeup) pics of me in a swim suit (gulp). At least it is a one-piece and my last suit.

I noticed that very few ladies were rocking the one piece on my Dominican vacation. Come on, one-pieces are cool, too!


This is a modified version of Kwik Sew 3780. I’ll show you what I did to change it later but first some basic details. I made a size small which is what I did for my last KS suit but for some reason this suit is too tight. It’s not terrible, just a little hard to squeeze into and you can see my black serger stitches on the side.

This makes me wonder because for my black monokini I made a S and the bottoms to that same pattern I also made S and they fit well. If I made a size M like on my purple suit I know this one-piece would have been too big. Next time I’ll go halfway between a S and M for this pattern. It’s weird because I thought KW swimwear sizing was pretty consistent. I already know that if I make a size S that I should lengthen the pattern pieces slightly but it was the width, not the length that was the bigger problem.

The fabric is from Fabricker here in Austin, one of the only local places that sell some swim fabric.

Again, I added my fave swim cups from Sew Sassy. I seriously love those things!

Ok, so, modifications – I added gathers on one side that creates a cool ruching effect. And it’s easy to replicate and you can do the same on any one-piece swim pattern.

First I traced my front pattern piece and drew my horizontal slash lines.

Then I cut those lines and spread out the pattern piece.

To make sure I gathered the right amount I copied the notch marks from the original pattern piece.

Then I filled in the open places with scratch tracing paper that I wanted to use up but you can retrace the piece for a nice clean finished version.

The finished look makes ruching like this. You could even spread both sides of the pattern piece and have even ruching down the whole front of your suit.

Well, that’s it for the Week of Swimsuits! Tomorrow I’ll post suit pattern options for voting for the Swim suit sew-along so this is your last chance for suggestions!

Comments (30) for post “The Week of Swim Suits Grand Finale: Kwik Sew 3780”

  • I recently bought a swimsuit and it was a one piece too! They’re so flattering! Even for skinny girls like you and I. I love your addition of shirring at one side. Super cute!

    • I agree, one-pieces don’t have to just be for women who want to cover up trouble spots. They can really highlight a nice figure on anyone.

  • This is my absolute favourite by far! I love the pattern but I think it is the addition of ruching that really makes it πŸ™‚ Nicely done!

  • Totally love it! Especially the gathering. Perhaps it was the fabric that was affecting the size? Does the black swimsuit fabric have a different amount of stretch to this one? I wish like crazy I could find swimsuit fabric as nice as this in my town!

  • I love this one!! Ah! I love them all! I’m so seriously impressed with these swimsuits. But I think the side ruching really makes this one special. I remember when I was in Italy a few years back I was amazed by all the totally skimpy bikinis on women of ALLLL ages and ALLLL body shapes. It was kind of liberating – but I remember also feeling that the one piece wasn’t getting enough love. They are really adorable.

    • Yeah, there were many a European lady in a skimpy bikini on this trip. I’m in no way against two-pieces (obviously, ’cause I made two) but I wish more women could feel comfortable in any kind of suit and not feel like the odd one out in a one-piece. Thanks Sallie!!

  • I love the swimsuit. I’ve never been able to wear one piece suits because I have a long torso and I feel squished like an accordion. Maybe if I ever get to sew as great as you I can modify a pattern to fit me. Excellent job on the swimsuits! Very impressive! πŸ™‚

  • Love this one too! Great fabric. I remember at one of our meetups a while back, Roseanna said that she always buys twice as much swimsuit fabric as she needs, because the first one is always a muslin due to the dramatically different stretch factor in each fabric. That’s probably the culprit, rather than the pattern sizing?

  • This is by far my favorite. I love the fabric, ruching and the one shoulder. I think it would fit many different body types as well.

  • Great swimsuit! It’s a really nice print – could you tell us what is the composition of the fabric? I’m guessing that the different sizing your experiencing is due to differing amount of stretch in the fabrics rather than the patterns being inconsistant.

  • Love it! The fabric is really great too. I adore one piece suits, but I feel like they look terrible on my shape – pear with no boobs. What’s a girl to do? Add underwire?

  • hello, I have a different one shoulder swimsuit pattern, that does not have the ruffle on top… How would I make and add a ruffle? Would I need to cut it on the bias, and also how to attach it?

Leave a Reply to Cristy Cancel reply

Your email address will not be published. Required fields are marked *

SidebarComments (30)