Combine water, sugar, and blueberries in a saucepan. Bring to a simmer over medium heat, stirring until the sugar is dissolved. Remove from heat. Using a fork, lightly mash the blueberries. Allow mixture to steep for about 30 minutes. Strain into a clean container. Store in the fridge until ready to use.
In a Collins glass filled with ice, add 1 ounce of vodka, pour ginger ale about 3/4 of the way up the glass and then add about 1 ounce of blueberry syrup. Syrup amounts may be adjusted to preferred sweetness. Stir before drinking.