Add fresh mint (leaves only) and granulated sugar to a large pitcher. Muddle together to breakdown leaves into smaller pieces with a long wooden spoon or muddling tool.
Add vodka and lime juice, stir until sugar dissolves. Add cranberries and cranberry juice, refrigerate until serving, up to 24 hours. Add ice and soda water, serve in stemmed cocktail glasses, including a few of the whole cranberries and a lime wedge.