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PDF Pattern · Video Tutorial Boys' Swimming Trunks

Bali

Stretch swim trunks with a lined front gusset for comfort, side-seam construction, and a soft fold-over elastic waistband finished with a twin-needle hem.

Boy on the beach wearing sunglasses and teal ocean-wave print swim trunks, with front and back technical flat sketches of swim trunks alongside
3 – 8 yrs Sizes included
25–30 cm Main fabric, by size
23–27 cm Lining fabric for gusset
2 cm Elastic width for waistband

Comfortable swim trunks, ready for the water

These boys' swim trunks are built from a front and back leg piece plus a side part on each leg, with a lined gusset for comfort and a soft fold-over elastic waistband — no zippers or closures needed.

Sized from 3 to 8 years (98–128 cm height).

What you'll need

Suggested fabrics

For swimwear, we recommend fabric mostly made from nylon, with at least 10–20% Lycra or spandex. Polyester blends with the same percentage of spandex also work well.

For sewing, use special needles marked STRETCH 65.

Also needed

  • Lining fabric for the gusset
  • Elastic tape for the waistband — 2 cm wide
  • Threads to match the fabric
  • Seam allowances are already included on every pattern piece
Before you cut

Fabric consumption

Tap a size to see it highlighted across the table. Values shown in cm / in.

Height (cm) 98
3 y
104
4 y
110
5 yMOST PICKED
116
6 y
122
7 y
128
8 y
Main fabric 25 cm
9.8"
25 cm
9.8"
27 cm
10.6"
29 cm
11.4"
30 cm
11.8"
30 cm
11.8"
Lining fabric 23 cm
9.1"
24 cm
9.4"
25 cm
9.8"
26 cm
10.2"
27 cm
10.6"
27 cm
10.6"

When buying fabric, keep in mind that the material can shrink, so take a margin of 5–10%.

Cutting list

Specification

Pattern piecePcs.
Main fabric
1 — Back pant leg2
2 — Front pant leg2
3 — Side part2
Lining fabric
4 — Gusset2
Support pattern
5 — Elastic into the waistband1

Attention! All our patterns already contain 1 cm / 0.39" seam allowances.

Step by step

Sewing instructions

Description of tailoring

14 steps
  1. 1

    Cut out the swimming trunks details from the main fabric. Cut out the gusset from the lining.

  2. 2

    Serge the outer curved edge of the gusset details. Press.

  3. 3

    Pin the gusset details together with the right sides along the inner curved edges (crotch). Serge it.

  4. 4

    Pin the back details together with the right sides along the crotch and serge it. Pin the front details together with the right sides along the crotch and serge it.

  5. 5

    Pin the side details to the back with the right sides together, aligning the notches. Serge it.

  6. 6

    Pin the side details to the front with the right sides together. Serge it.

  7. 7

    Pin the front and back together along the inseam with the right sides. Pin the gusset to the inseam with the right side to the wrong side of the back. Serge it.

  8. 8

    Press the gusset to the front.

  9. 9

    Pin the gusset to the front upper hem and baste it.

  10. 10

    Stitch the elastic into a ring.

  11. 11

    Pin the elastic to the upper hem of the garment (to the wrong side).

  12. 12

    Serge it.

  13. 13

    Fold the elastic inward and pin. Sew in place using a twin needle.

  14. 14

    Fold the bottom hem of the trunks and pin, making sure the gusset is pinned to the front. Sew in place using a twin needle.

The swimming trunks are ready!
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