Octonauts Halloween Costumes

It’s been almost 10 months since the Octonauts entered our family’s lives and my boys are still absolutely bananas over those loveable little deep sea explorers! We’ve already had one Octonauts-themed birthday party and if the obsession continues, we might have another one in February!

I wasn’t at all surprised when I asked the boys what they wanted to dress as for Halloween and they both promptly replied “OCTONAUTS!” The only problem was deciding which Octonauts character to choose! After much deliberation, Miles decided to go as Captain Barnacles (a polar bear) and Spencer as Peso Penguin.

DIY Octonauts Costumes

I realize they will get a lot of “…*stare*…And who are you supposed to be??” questions this Halloween, but what should I do? This is what they want! They can bill me later for the therapy sessions from having costumes that suck, of the Unidentified variety.

Captain Barnacles

Miles’s costume was very simple to put together. Here’s what I used to assemble his costume:

  • Dark blue turtleneck and pants (from the closet)
  • Dark blue rain boots (purchased at Once Upon A Child)
  • Homemade Octonauts hat (using felt and a printed Octonauts logo from UnderseaHeroes.com)
  • Belt with faux Octo-compass (using ribbon from my craft/material stockpile and a golden plastic coin from our dress-up items)
  • Scissors, glue, and

Captain Barnacles

The most difficult part to put together was of course the hat. I used the same basic idea from Spencer’s Octonauts birthday party earlier this year except I used felt for longer durability. I’m sure there’s a way to make it better, but I’ll be honest – I wanted quick and easy. I used Heat’n Bond to put the pieces of the hat together and glued on the logo. The “Octo-compass” is just a coin glued to the ribbon.

Peso Penguin

Spencer’s costume was a little more difficult but was still very simple. Here’s what I used to assemble it:

  • Black turtleneck (the same one we used for Miles’s Mickey Mouse costume last year, actually!) and pants (from the closet)
  • Dark blue/turquoise rain boots (also purchased at Once Upon A Child) and YES I realize Peso doesn’t wear boots but my son insisted on boots.
  • White sailor’s hat, turned inside-out, from our dress-up bin with an Octonauts logo attached to it
  • Felt on the shirt’s front
  • Felt (and another Octonauts logo) for the medical bag. I would have used a small white box with a handle if I’d had one, but decided this would work too!
  • Scissors, glue, and more Heat’n Bond

Peso Penguin

I cut out a large oval of white felt and used Heat’n Bond to attach it to the front of the black turtleneck.

I got lazy-creative with the little felt medical bag and just whipped something up with the Heat’n Bond. As you can see in the photo, the Heat’n Bond didn’t hold perfectly, so I need to fix that before Halloween.

Edited to add:  I did end up going back and fixing these by crappily stitching the penguin belly, medical bag, and hats because I didn’t trust the Heat’n Bond to hold up through wearing their costumes 2-3 times for multiple events.

Here’s a photo of the whole Octonauts gang. How did I do with the costumes?

For more Octonauts costume inspiration, check out UnderseaHeroes.com!

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About Krista

Krista is a full-time working mom of two boys, currently aged 6 and 7. She lives in Kentucky with her husband, Brandon.


  1. Looks great!!! I love their costumes!!! Miles’ is perfect. It was very clever to just add white felt for Spencer’s. My only concern would be the collar. C llooovvveeeesss the collar. Would Spencer allow you to add the blue collar to the turtleneck? I’m not even sure how you would make it work. :/ I’m thinking Steve convinced C to be Kwazi as he has a patch and patches are cool. I would gave to figure out a CAT costume aaannnddd the Octonauts gear. Gah! I did see some blue tennis shoes on clearance at KMart the other day- problem was they were ALL in a wide-width. I wish we had a OUAC in my area. 🙁

  2. Funny you mention the collars…So, I made some, out of felt (LOVE felt, can you tell?) but since they both had turtlenecks, I thought it would look dumb. BUT I might attempt it. If I do, I’ll update here.

    The boys each at one time mentioned Kwazii but I’m pretty sure they would refuse to wear the eye patch :/ Miles has to wear a real one (a sticky one) for his eye condition anyway and HATES IT so it’s kind of a sore subject.

  3. Yay! So cute! I LOVE making costumes and think they are so much cooler than store bought ones. I made Gillian a RAINBOWDASH! costume for Halloween this year () and Langley wants to be a “bampire” so I have to figure out something to do for him for that.

  4. Where is Once Upon A Time children’s boutique? Sounds neat.

  5. Hey! I’m making my son an Octonauts costume for Book Week this year (he has an Octo book, so I say it counts as a book character) and this has helped me heaps with the costume. Also, you crack me up. So double thank you for the help and giggles.

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