The backward flow of water that slides down the beach and back toward the sea after a wave crashes. You feel it tug at your ankles as the water runs out.

Why it matters: Undertow helps water return to the ocean and can shuffle sand, shells, and small stones. It can knock over kids: be careful, step back if the pull feels strong and hold an adult’s hand.

Fun fact: Despite the name, undertow doesn’t suck you under like a vacuum; it flows outward along the bottom.

Say it like this: UN-der-toe

Activity twist: Tray Beach! Tip a baking tray with a towel “beach” on one end. Pour a cup of water up the towel (the “wave”), then watch it rush back down: that’s your mini undertow!

We have something for you: Download and colour a short adventure of our Bubble Buddies.