Swim Hats Chart

XS

17.5″ / 44.5 cm

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Best fit for babies and toddlers

S

20″ / 49 cm

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Available in reversible hats only

One Size

Up to 21.5″ / 54.6 cm

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Fits kids of all ages and most adults

XL

21.5″+ / 59.7 cm+

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Best fit for above-average head size

nammu sun protection swim hat size chart
  1. Grab a flexible tape measure — or use a piece of string, then lay it against a ruler.
  2. Wrap it around your head just above your ears, angling slightly upward across your forehead.
  3. Note the measurement in inches or cm, then match it to the size cards above.

Between sizes? Go up for a looser fit, or down for a snug, secure hold — especially for water activities.