Power Sports Bra Strappy Swim Top Hack

Power Sports Bra Strappy Swim Top Hack

Posted by Melanie Burns on

Hey y'all, it's Melanie, the resident Greenstyle Power Sports Bra hack addict. With all the excitement around the North Shore Swimsuit sew along that the wonderful Sharon Aguilar is doing on her blog, (You can find it HERE, if any of you missed it), I'm motivated to sew ALL THE SWIMSUITS!

I've been pretty actively perusing Pinterest lately, and I've seen so many cool strappy swim tops. In true sewist fashion, I thought to myself, "I can totally make those!" I've got quite the obsession with the Power Sports Bra, and it's such a great pattern base to use for so many cool looks. I saw one strappy back version that a member of the Greenstyle Facebook page, Caitlyn MK, made (she's an amazing sewist, and you can check out her makes on her blog here). I contacted her and asked if I could use her version as inspiration for my swim top, and she of course said yes.

It took a few tries to get all the little details just right, but I think you can agree, the final result is pretty awesome! Now that I have done all the hard work for you, I'm going to explain my process step by step so you can make one of your very own! 

Disclaimer: I based this top on the 28C Power Bra pattern pieces and measurements. You will have to modify these pieces based on your own measured size. 


I used Tropical Paradise swim fabric from The Styled Magnolia for my main, and solid Plum swim fabric from Made Whimsy for the straps, band, and the lining. It took me less than 1/2 yard of each to make the whole top. 

I used 3/8" swim elastic from Joann's for the straps, 1/4" clear elastic from Amazon for along the seam allowance of the front pieces, and 1 1/2" sport elastic from CreateForLess for the band.

Let's Get Started

I slightly modified the center piece of the Power Sports bra so it had a 3" rise in the middle. This gives it a little lower neckline without allowing the spillage I usually get with triangle or deep V swim tops. I measured 3" from the bottom and marked it on the fold line, and just graded the curve to make it a smooth line to the new neckline. 

I made one long strap to cut down into smaller pieces instead of sewing and turning a bunch of little straps. For my size, I was able to use the existing strappy Power Bra pattern piece as the width, and just cut across the whole width of the fabric, which was 60". I ended up with a piece of fabric that was 1 1/2" wide by 60" long. I folded that piece in half width wise and lined up the 3/8" swim elastic to the raw edge. 

I serged the elastic along the length of the strap, stopping the elastic 2" from the end of the fabric. This will eliminate the bulk when creating the loop in the back center strap (shown in a later step). Turn the entire strap, making note of which end has the shorter elastic. 

With my strap made, I cut out all the other pieces needed. I cut the center and cups of the PSB of both the main and lining fabric, then the waistband out of the solid. I used the pattern piece for the 1 1/2" band.

With my pieces cut out, I constructed the front as directed in the Power Sports Bra instructions. I cut an extra 1/4" off of the sides of the strap insert slots to account for the thinner strap, since we're only using one strap and the Power Sports Bra uses two. 

Now came the time to measure out my straps. I used the racer back pattern piece of the Power Sports Bra as my template. I folded the strips in half and laid them across the racerback pattern piece to get the length measurement.

I marked on the actual pattern piece where I wanted the straps to line up with the side seam. I started at the top, measured 3/8" down from the top and drew a line. I made each "strap" line on the pattern piece 1/2" wide to allow for a little wiggle room when attaching. I measured 1/2" down from the bottom of that placement line and made another 1/2" strap line, and again measured another 1/2" down from that line and made another strap placement line. I ended up with 3 strap placement lines that were 1/2" wide and 1/2" spaced apart. With the straps lined up with my guidelines on the pattern piece, I then cut them to the proper length determined by the width of the racerback pattern piece. Since the body gets wider the further up the ribcage it goes, I got 3 slightly different measurements for each strap. The bottom strap was 12", middle was 12 1/4", and top was 12 1/2". Once I got those straps cut, I transferred the line markings to the side seam of the already constructed front piece. 

I lined up the straps with my markings and basted with my sewing machine to keep them from shifting while serging. I then serged the side seam, and repeated for the other side. Once straps were serged into place, I turned the top right side out and tacked the straps down right along the seam line to provide a little extra stability and prevent pulling (shown here on the top leftmost strap in the picture below).

Here is what we have completed so far.

Next, I marked the center of each strap to make sure our center back vertical strap would line up well.

Now it was time to fold over that strap piece with the short elastic to create a loop. I used the triple zig zag stitch, stitch number 5 on my machine, set on the longest stitch width and shortest stitch length setting. This stitch was the perfect width to make sure the strap was stitched nice and centered.


I folded the end without the elastic in it over 1" and stitched using the above stitch. I then determined the center back strap length by placing it against the side seam and cutting at the height I wanted. Mine ended up being about 6" tall. 


Then, I triple checked that the vertical center strap was completely centered on the horizontal straps.

Check one: I lined up against the racerback pattern piece I drew on to make sure the horizontal straps were evenly spaced along the vertical strap.

Check two: I pinned the vertical center strap along the center of the horizontal straps using my racerback piece as the template.

Check three: I folded the straps in half yet again and clipped the side seams together to fully ensure the vertical strap was indeed centered. Trust me, you won't regret being this thorough! 

Once I was absolutely sure it was centered, I sewed the vertical strap to the back of the horizontal straps using the three step zig zag stitch I used above. I tacked it down at the top and bottom of each horizontal strap to minimize the stress on those stitches.

Now I got the remaining section of strap I had left over from cutting the smaller pieces and stitched it to one of the front strap inserts. I had 15" of strap left of the original 60".

Once I inserted and sewed that strap in, I turned that side right side out, threaded the strap through the loop in the vertical strap, and pinned it to the other side's strap insert. I wanted to try it on before sewing that side in to make sure it was the right length. 

I then sewed my waistband on 2/3 of the way around, leaving an opening under the entire cup on the side I hadn't attached the strap into the insert, so I could turn and stitch that strap once I determined the length.

I always sew the waistband partially on because I get a more accurate feel of strap length when I try it on. I tried it on and needed to shorten the strap 1" for it to fit comfortably and feel supportive. Once I shortened it, I sewed it into that strap insert, threaded the elastic into the band, then finished attaching the underbust band completely. To finish it off, I topstitched the serged seam allowance down toward the band with a zig zag stitch on my machine, and voila! It was finished!

I borrowed my friend's toned and tanned body to model the final set for me! I paired this strappy top with the North Shore scoop bikini bottoms. They're my absolute favorite bikini bottom ever. They're just cheeky enough, but not so much so that you don't feel comfortable chasing after children, pets, or runaway frisbees. 

I hope y'all enjoyed this tutorial, and I look forward to seeing your versions! Don't forget to post them to the Greenstyle Facebook page!



P.S. Keep a look out for my next PSB/North Shore hack ;)

Over and out. 

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