Place the chopped cucumber, avocado, fresh mint leaves, coconut water, lime juice, ripe banana, and coconut milk into a blender.

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

If the smoothie is too thick, gradually add more coconut water and blend until you reach the desired consistency.

Taste the smoothie. If needed, adjust the sweetness or texture by adding more banana or coconut milk.

Pour the smoothie into glasses.

Serve the smoothie chilled. Optionally, garnish with a mint sprig or a slice of cucumber.