Add the raspberries, diced apple, and water to a blender. Blend until smooth. If you prefer a seed-free texture, strain the mixture through a fine-mesh sieve.
Pour the mixture into popsicle molds, leaving a little space at the top for expansion. Insert popsicle sticks.
Freeze for at least 4-6 hours or until fully set.
Run the molds under warm water for a few seconds to release the popsicles.