Halloween 2022, The Shark

Designing, pattern cutting and sewing a children’s Shark onesie/Halloween outfit


Please note, all fabrics mentioned and their suppliers, I don’t know whether they are still available at the time you are reading this post. If not, I’m sure they’ll have other lovely ones for your projects. I did not get paid or sponsored by any of them to use them either, it was all personal choice to do so and personal choice to mention them.


Writing about Halloween costumes after Halloween, when we’re heading towards Christmas, may feel a bit odd, but I thought, why not! I’m guessing also as I made 2 for this year. This one will be all about the Shark and another one will be covering the Unicorn Witch. Hope you enjoy reading the one you chose, or both!



The two costumes I was asked to make this year was a Shark and a Unicorn Witch. The minute you mention shark, we all hear that music don’t we? Dun-nun! Not to mention, get this image of the fin appearing above water and thinking, uh-oh! Not the one asking me for this
outfit though! According to him, sharks are cute! Well, okidokie! Let’s change everyone’s minds then and show how cute sharks can be!


It is amazing though, how little we remember details when we’re asked about these things, as I did have to think beyond the fin. How do their heads look, there are different types too, so
which shark are we going for? I was quite happy it was the popular great white that was wanted. A hammerhead could have been interesting to make though! I then thought, why not make the outfit handy for after as well? Something that can be worn around the home? Winter is coming, so something nice and snuggly and warm will be handy. A onesie! Halloween can sometimes be cool weather, a nice onesie would mean no thick winter coat would be needed, taking away the image.
Having made onesies before (I made an astronaut onesie years ago for example, the orange one they wear under their space suits), I was ready for this one! I also looked up references of shark onesies online, to make sure I wasn’t missing any important detail. 


Pattern Cutting 

I used the Winifred Aldrich book I have for Children’s wear for reference, as it covers baby wear for a whole chapter. Including, indeed! A onesie! Baby onesies, are basically the same as the ones for children’s and adults. Only difference is, that babies need extra space in the hip area to fit the nappies they wear, so I left that bit out of my pattern cutting. Not to mention those cute little footsies, they got traded for a regular hem. Apart from that it was all pretty much as the book wanted me to do it, but bigger size. I drew the hood to fit onto the neckline and made the top bit slightly longer, so it would cover the head more, like a shark’s mouth would. Working out the fin was great fun! How often do you get asked for this type of thing? The first one I drew and made, did turn out to be too small when placed on the back, but it helped get the second one perfect! The pattern basically looked like a sail in the wind.


If you want to make a shark onesie, but don’t know pattern cutting, you can buy an existing pattern with a hood and make adjustments to it. The fin is really easy to draw! And you can first pin it to check it’s in the right place, before sewing up the back seam. 



Quick note: I know it’s boring to do, but do always wash and iron (where needed) your fabrics before starting your project. This takes out shrinkages and any dye that perhaps didn’t stick 100%. This will wash that away.  

For the fabric, it had to be something to keep the wearer warm, be easily washed, as we all know kids spill food easily and just love to run and climb. I found a lovely sweatshirt, fleece backed fabric with Tia Knight fabrics. A high cotton blend. I am a big lover of natural fabrics myself, as they are so lovely to work with and wear. They really do help us retain our body heat during colder times and helps us regulate our heat when it’s hotter, keeping us cooler. Not to mention, they usually wash so wonderfully well too! I also got some red cotton jersey from them and some ivory scuba for the tummy and teeth. As scuba has structure, I knew it would work really well for the teeth without the need of interfacing.

I got the eyes and cuffing fabric at the knit and stitch show, at the Alexandra Palace. I unfortunately forgot the shop names I bought these at. The eyes are regular toy eyes, with the locking system at the back. As I knew I was going to line the hood and the wearer being old enough, I knew I could go for these.

Do always check they are still tightly on, before putting a child in the onesie of course and remove if you notice anything wrong with them.

The stuffing used in the fin, I bought from ribbon moon, it’s regular toy grade stuffing.


Sewing onesies is pretty simple to do. As my dressmaking teacher taught me, I first made the back one piece and the front one piece. Meaning you do there what you need to do first. Be it darts, a seam, a pocket. In this case, It was first making the fin, as that one gets attached in between the centre back seam of the onesie. Once the shark fin was sewn up, I always put V-cuts into the curved seam. This helps the fabric move into itself when folded inside out. As you give it the space it needs. Otherwise you’ll notice there is too much fabric happening there and your line won’t sit nice and flat. After that I stuffed it with toy stuffing. I used some tweezers to get it into the point and then filled it onwards from there, till I was happy with what I was seeing. The fin was then sewn onto one of the back pieces, so it would stay in place while the whole seam would be sewn up. It is awkward pressing the seam open with the fin, but not impossible. Just make sure you don’t press down when the fin is under where you’re pressing, you don’t want the fibres of the filling to be squashed together.

The front of course needed it’s big white tummy! As the pattern is curved at the corners, I first put V-cuts into the seam allowances. This means there is no excess fabric there to struggle with being pushed in. The V’s create enough opening for the fabric to close there when folded inwards. To make sure it wouldn’t sit funny when on, I pinned the tummy on, while it was on my big ham. This is to replicate the curves of our body. Once I was happy with it all, I top stitched the tummy pieces on and I could sew the Centre Front seam to where it was needed as I was using a YKK regular zip. To help things, I make a line onto the zip with tacking thread, showing me where the tummy lines up. This way I know where the zip needs to connect on the other side.

Back and fronts being done, they could go together and the sleeve going in. Hey presto, it’s starting to look like a shark onesie!

Next came the hood. Construction of it was the same as any hood. One outer shell, one lining. I measured the width of the hood that needed the teeth and calculated how many teeth of 2cm wide I’d need to cover the whole hood. The pattern for it is literally a triangle, nice and easy to do. I decided on making the teeth double fabric, as that way they’d be able to stand up by themselves more and no fraying or anything happening. They were sewn very quickly, the seam allowance just needed trimming and they needed pushing right side out. Once they were done, I started from the centre middle of the hood and made my way to each edge pinning the teeth in place. Making sure I didn’t miscalculate anything. I loved the look! The teeth were sewn into place onto the blue hood, this was again to make sure nothing would move when attaching the lining. But where should the eyes go! This was a nerve wrecking one, as you need to make small holes to push the pins the eyes are on through the fabric. Checking a photo of a real shark, their eyes are on their sides. Not on their front. Good thing I checked! I know I wasn’t doing anything National Geographic worthy here, but I still wanted to make sure, nothing felt or looked out of place. Pinning the eyes on first so I could check helped and they could go into place. Stitching the whole hood after, it all looked hilarious to me! Seeing it on the Styrofoam head, it just all came to life! To prevent the lining from going all over the place when worn, I stitched the seam allowances of the lining and the blue hood together on the inside. Stitching through and through, through the seams, can create a messy outcome if you don’t line them up exactly. Hence I prefer this, it keeps the whole hood in place perfectly.


Final Look

With the hood finished, it was now all about finishing it all up. The cuffs on the wrists and ankles, you calculate by measuring the wrist and ankle hems of the onesie first. This measurement you x by 0.85. Now you have the measurement you need for the ribbing fabric. This is always a little bit smaller than the area it is going to be attached too. The reason for this, is so that it closes more to the body, keep you nice and warm. When pinning it on, I first pin it onto 4 spots. The 2 half points if that makes sense. And then the bits in between you have to gently ease the cuff onto the sleeve and ankle hems. Don’t stretch the hems though! Just let the machine grab those and move them along. Only help with the cuff fabric, easing it in place on top. If you stretch the hems, you may get some puckering. Take it nice and slow and you will be absolutely fine. 🙂

The hood got stitched on with the blue part by machine onto the onesie and the red part by hand sewing. This gave it a nicer finish and there would be nothing to possibly irritate the skin while being worn.


The easy thing with the shark onesie is, that you don’t really need accessories! You put it on, you’re ready to go! Or ready to lounge! Whichever you want to use it for.



And here he is! The shark! Dun-nun! I mean…how cute! 




















Rundown of places used (again, I did not get sponsored or asked to name them):

tiaknightfabrics.co.uk – Sweatshirt with fleece backing fabric, ivory scuba and red cotton jersey

Zip is a regular YKK zip in ivory, which you can easily get at fabric stores or online.

The cuff fabric, I unfortunately forgot the store name. But search for cuff fabric and you will find it easily. 🙂

Action shots were taken at Barleylands Farm Park, during Spooky Nights.


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