Children’s Waterproof Swim Bag Tutorial

Whether your little one is lucky enough to be heading to the beach or pool on a summer holiday, or attending weekly swimming lessons, a swim bag with waterproof lining is perfect for keeping soggy swimsuits and accessories in and yourself dry!

Children’s Waterproof Swim Bag Tutorial

This swim bag is fully lined with waterproof fabric, even in the front pocket. This makes it easy to carry all of your swimming essentials without getting your clothes or other surfaces damp.

We’ve designed this to be the perfect size for your little one’s swimming kit – think goggles, costume, small towel, swim cap, sun cream (although the giant inflatable flamingo you’ll inevitably acquire will need a slightly bigger bag!).

You’ll also be learning how to sew using our fantastic PUL fabric, which is not only waterproof but breathable, how to insert a chunky zip, line a pocket and create a drawstring top for your bag, which can all be applied to variety of different projects, not just this swim bag! 

New to PUL Waterproof Fabric? Check out our fabric guide here to learn more & get some tips & tricks

We’ve also included how to cut and make a plain version of the bag, if you aren’t quite ready to tackle the zip, or if your child has suddenly remembered they have swimming tomorrow and you need to whip something up before bedtime!

It has a waterproof lining for soggy swimming costumes with a ‘dry pocket’ for any valuables. We have used the Rockpool fabrics from Dashwood Studio which we think the kids will love. 

Swim Bag features:

  • This swim bag is fully lined with a waterproof lining so you can keep wet swimming togs away from anything else you wish to keep dry!
  • It features a waterproof front zipper pocket to keep your undies dry or store electronics away from the water
  • Drawstring closure – easy for little hands to open & close
  • If you feel the zipper is pushing your sewing skills, there are also cutting instructions for a bag without the zipped pocket

If you would prefer a printable PDF version of this tutorial you can request a copy is sent to your inbox here

Boring Legal Bit: If you follow any tutorial or guidance found in this post, or on this blog, you agree to be bound by our disclaimer which can be viewed here

A sewing project for: Confident Beginner

Finished Dimensions: 39cm x 36cm approx

Approximate sewing time: 1hr 30mins (allow extra time if you are a novice)

We have also provided cutting instructions to omit the waterproof pocket 

Important Notes:

  • 1cm seam allowance throughout, unless directed.
  • For steps using machine sewing, straight stitch, backstitching at the start & end using stitch length 2.5 unless otherwise stated.
  • Prepare your fabrics as per manufacturer’s care advice
  • Seams have been finished using an overlocker, but the raw edges can also be finished on a sewing machine using a zig zag stitch, or left as the project is fully lined
  • Quilting clips have been used as pins can create holes in the PUL which do not recover
  • The PUL has no ‘Right Side’, but we like to use the ‘shiny’ side as the RS as it feels more comfortable during use – just make sure whatever you choose is always your RS
  • We recommend cutting the PUL with a rotary cutter and mat to avoid using pins, but you can also use pattern weights and scissors
  • All materials can be purchased from our online sewing superstore Plush Addict.

Materials you will need…

Item:Amount required:We used:
Fabric A: Cotton fabric for side and back panels40cm x 110cm (16” x 44”)Dashwood Studio – Rock Pool – Shells And Fish
Fabric B: Cotton fabric for middle and pocket panels30cm x 110cm (12” x 44”)Dashwood Studio – Rock Pool – Barnacles White
Fabric C: PUL waterproof fabric for waterproof lining40cm x 140cm (16” x 56”)Plush Addict White PUL Fabric (Polyeurethane Laminate fabric) – Waterproof Breathable Fabric
Cord for the straps3m (3 3/8yds)4mm Polyester Braided Cord – Navy
20cm/8” zip1Dual Colour Plastic Chunky Style Zip 20cm/8”

Sewing Kit You Will Need:

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If you would prefer a printable PDF version of this tutorial you can request a copy is sent to your inbox here

1) Cut out your fabrics:

To create a colour blocked bag as we made, cut:

From Fabric A Cut: 

  • Front side panels: two 9cm x 42cm
  • Back: 37cm x 42cm
  • Side tabs: two 4.5cm x 8cm 
  • Zip tab ends: four 3cm x 4cm

From Fabric B cut:

  • Front middle panel: 23cm x 44cm
  • Front pocket outer: 19cm x 23cm

From Fabric C cut: 

  • Front and back lining: 37cm x 42cm
  • Pocket bag (outer pocket): 19cm x 23cm
  • Pocket lining panel: 20cm x 24cm

To create a bag in one colour, without the zip pocket/panels cut:

Front outer: 37cm x 42cm

Back outer: 37cm x 42cm 

Front and back lining: 37cm x 42cm 

Side tabs: two 4.5cm x 8cm 

If constructing your bag in one colour without the zip pocket/ panel, skip straight to the ‘Assembling the main bag section

Inserting the zip:

For this section use your zipper foot on your machine.

2. Finish the edges on your zip tab ends using an overlocker or zig-zag stitch. Place one right side up (RS), with the zip facing up (teeth side up), sandwiched with another zip tab end RS down on top. Sew together near the end of the zip.

3. Fold the zip tab ends away from the zip, flat, so that you can see the zip end fully. Press in place (avoid catching the zip with the iron!) Topstitch the zip tab ends down, keeping them in place and flat. Repeat this with the other zip end.

Swimming bag sewing tutorial - insert the zip

4. Take your outer fabric pocket piece, and the PUL outer pocket piece and sandwich the zip between them, RS together.

5. Flip the zip RS up between the pieces, and top stitch the seam flat in place.


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Swimming  drawstring bag sewing tutorial - insert the zip

6. Take the larger PUL pocket panel and tack in place on the outer front middle panel both with RS up, along the top only. 

7. Take the pocket bag with zip attached and place it on top of the outer front middle panel. The lower edges of the pocket will need to meet with the bag front after we have folded it to attach the zip.

8. Fold the bag front on itself using the extra 2cm, above where you want the zip to be, to create a folded edge to attach the zip and pocket bag to the front of the bag.

9. Sew the zip to the bag’s outer middle front.

Sew a  drawstring bag sewing tutorial

Assembling the main bag:

10) Put the bag sides on the outer bag front, RS together. Sew each side seam, press flat. Topstitch the seams (optional but achieves a more professional look!)

Assemble the drawstring bag  - sewing tutorial

11.To create the loops for the straps, fold the side tabs in half, RS together, lengthways and press. Stitch along the long raw edge. Turn the loop out and fold in half again, press. Lay on top of the outer bag front in the corners, a little from the bottom remembering the seam allowance.

Assemble the drawstring bag  - sewing tutorial

12. With RS together, put the back outer piece on top of the front outer piece, measuring 4cm down from the top of the bag sides, marking with a clip or tailor’s chalk. Stitch down the sides and bottom from this point to the other side 4cm down

Assemble the drawstring bag  - add the straps - sewing tutorial

13. Repeat the construction of the main bag for the lining also. The lining will come up to the top of the bag for a neat finish. 

14. Place the bag out RS together inside the bag lining. Sew around the top of the bag, leaving the side seam openings you made by measuring down 4cm, and a small gap in the top back of the bag for bagging out.

15. Bag out and slip stitch the opening shut.

Creating the drawstring channel:

16. Sew across the top of the bag front and back in line with the opening you created, catching the seams flat inside the channel and backstitching at each end.

Create the drawstring channel for the drawstring bag - sewing tutorial

Adding the drawstring straps:

17. Cut two pieces of cord to 1.5m in length (adjust as necessary). Using a safety pin thread one piece through both top casings, so the end comes out the other casing on the same side of the bag.

18. Repeat with the other side.

19. Knot each cord through the side tabs on either side of the bag. 

And you’re finished, well done!


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