DIY Baby Pirate Costume

Introduction: DIY Baby Pirate Costume

About: We're Jaimie & Jay! We make DIY Halloween projects on YouTube. Helping you make awesome and spooky stuff.💀

We both love going to the Renaissance Faire and we always dress up in full costume to get the most out of the experience! This year was our son Cullen's first time and we made sure he was going in style by making his very first baby pirate costume to match Jay's. The puffy pirate shirt is made from white muslin fabric (it was actually one of his old swaddles!) and the pirate vest is just some basic brown fabric. We used a piece of grey/silver fabric with some nice shine for the pirate sash and that was it! Very easy, simple and cheap materials and so much fun to make. It also makes a perfect Halloween Costume!

The puffy white shirt has elastic wrists and the bottom is actually a onesie so it buttons up! The vest is meant to hang down to his thighs and a sash of any kind of material is tied around the waist.

This costume is less about curly mustaches, stripes, and eye patches, and more of a ren faire style outfit and we did it this way to match Jay's costume that he wears to the festivals. They ended up matching perfectly and Cullen even got featured on the front page of a local newspaper.

Total Cost: $5-10, depending on the fabric you choose

Total Time: 1-2 Hours


  • White/beige muslin fabric (or an old swaddle) (For the shirt)
  • Brown Fabric (For the vest)
  • A onesie/shirt that fits your child (for template)
  • A onesie/shirt you're okay with cutting up (for the snaps)
  • Gray/silver fabric (For the sash)
  • Thread
  • Rubber Bands (For wrist elastic)


  • Sewing Machine (or a needle and thread and a lot of patience!)
  • Scissors
  • Pins
  • Marker

Step 1: The Pirate Shirt!

First we laid out the white fabric and then using a onesie that fits him well, we traced around it. We gave it a few inches of margin around the outside of the onesie so that it would be baggy and give it a "puffy shirt" look.

We then folded over the material again and cut on the line we marked, making the whole thing symmetrical.

Once the pattern was cut out, we pinned it all the way around to get it ready for sewing. At this point the neck hole has not been cut out. The fabric is folded on the top edge there so that edge doesn't get a seem.

We then sewed up the sides and across the bottom of the sleeves using a straight stitch. We used white thread.

Once the sewing was done, we cut out the neck hole using our marked lines from earlier, then cut a slit down the front. Now we could finally do a test fit!

Step 2: The Pirate Shirt - Wrists!

At this point we did a test fit to ensure it was baggy enough. If it's too small it won't have that classic "puffy shirt" look to it. Another benefit of it being super baggy is that it will fit him for longer!

Maximum cuteness had already been achieved but there was much further to go! We used the marker to find where his wrists were, leaving enough slack to keep it baggy on his arms. We also marked where his waist line is on the shirt.

Then we cut both sleeves to be the same length based on where we'd marked them. After that we folded the wrist cuffs back about 1.5" and sewed TWO seems. One is 1/2" back from the edge to create a ruffle, and then another seem a little over 1/2" back from that one, which creates a channel for the elastic, or the rubber band in our case. These get sewn with a zig-zag stitch to allow for stretching.

We then cut two rubber bands in half and attached a safety pin to the end to help us feed it through the channel on both wrists. It's definitely better to use actual elastic for this but if you're on a budget, these work just fine.

Once both ends are through, we super glued it together and let it dry. Once dry, you stretch out the wrists and the rubber bands get pulled inside to create an elastic wrist! Make sure these aren't too tight for your baby's wrists.

Step 3: The Pirate Shirt - Waist!

Next we took the old onesie and cut off the bottom 1/3 of it so we could use the snaps. Then we slipped it around the bottom of the shirt at the waist line, using the mark we made at his wrist to figure out exactly where it should go. Once it was in place, we pinned it all around and sewed it using a zig-zag stitch to allow for stretching.

Last step on this part is to simply cut off the excess material at the bottom and the shirt is done!

If you have an older kiddo, this whole part is unnecessary but for us having it be a onesie was ideal.

Step 4: The Pirate Vest!

Next up was the baby pirate vest. Here we used the template onesie to trace the size of the vest, giving it a small margin around the outside of about an inch. It's still a little big but not quite as baggy as the shirt.

The arm and neck holes were roughly drawn in to whatever style works for you. We then folded the fabric, pinned it together, and cut out the template. We pinned it first in this case because the material is kind of slippery and wouldn't stay together if we hadn't. That would have resulted in two sides not being equal. This way, everything is clean and the same size.

Once it's cut out, we re-pinned it to make it easy for sewing, and we also pinned the shoulders. Next we sewed the entire thing together using a straight stitch. We used black thread for the vest.

We then marked the center on the top and bottom and connected the line on the front using a straight edge so we could cut the front in half, opening up the front of the vest.

The last step on the vest was to sew it all the way around outside. This material frays fairly easily so this prevents it from falling apart over time. This was done using a straight stitch and black thread.

Step 5: The Results!

Behold, Cullen the Beardless! First of His Name!

It's easy to make, affordable, and uses just basic tools but by far the best part about this project is seeing your smiling kiddo wearing it when it's finished. :) We hope you enjoyed our tutorial, now go out and make something!

You can also watch the full video, embedded at the top of this Instructable!

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