Pour in the frozen peach slices so they sit evenly over the watermelon.

Spoon the Greek yogurt into the blender, distributing it across the fruit for even blending.

Blend on high speed until the mixture becomes completely smooth and creamy.

Pause briefly and scrape down the sides if any fruit pieces remain unblended.

Blend again for a few seconds until the smoothie reaches a thick, velvety consistency.

Pour into chilled glasses and serve immediately while the smoothie is fresh and cold.