Add blueberries, cucumber slices, and honey to the shaker.
Use a muddler to gently mash the blueberries and cucumber. This releases juice and flavor.
Pour in the fresh lime juice and cold water.
Fill the shaker with ice, close, and shake for about 15 seconds.
Strain the mixture into a tall glass filled with ice.
Top up the glass with club soda or sparkling water.
Stir lightly to combine everything.
Garnish with cucumber slices, blueberries, and mint if I have some.