Good questions.

Every pair is printed with a heat-reactive pigment. Cool, each pair shows its first colour. Warm it up in the sun or in warm water and it shifts to the second: purple to blue, blue to green and orange to yellow, plus green to mint on Geometric. Cool water switches it back. See how it works

Look after them and they'll keep changing. Heat is what wears the effect down over time, so rinse in cool water, dry in the shade and skip hot washes, tumble dryers and the iron.

Men's shorts come in S to 3XL and kids' in S to 2XL. If you're between sizes, size up for a relaxed fit. Not sure? Send us your waist measurement and we'll help you choose.

Both have the same heat-reactive colour change, quick-dry four-way stretch, a mesh inner liner and a full elastic waist with drawcord, in S to 3XL. The Original is the bold, classic look. Geometric layers the colour change over a sharp triangle print, so it's a bit more subtle. See them side by side

Our kids' shorts are quick-dry with a full elastic waist and drawcord, in kids' sizes S to 2XL. They come in Purple to Blue and Orange to Yellow, the same as dad's Original. Want both in one go? Grab a Dad & Mini set.

We'll email your tracking link as soon as your order ships, and you can track your order here.

No dramas. Tell us within 30 days of delivery and we'll send the right size, free. It's part of our 30-Day Happiness Guarantee. Get in touch to start.

They're an easy one to get right. Not sure of their size? Go with their usual swim short size, or size up if they're between sizes. If they don't fit, our 30-Day Happiness Guarantee covers a free size swap.