Add the blueberries, lemon juice, honey, and cold water into a blender.
Secure the lid and blend on high speed until the mixture is smooth and the blueberries are fully broken down, about 30-60 seconds.
Stop the blender and check the consistency—should be icy, thick, and slushy. If you prefer it more frozen, add a few more ice cubes and blend again briefly.
Pour the blueberry slushie into glasses, allowing the vibrant purple color and icy texture to showcase its inviting appearance.
Garnish with a few fresh blueberries or a wedge of lemon, if desired, for an extra touch of freshness.
Serve immediately with a straw or spoon to enjoy the refreshing, icy texture.