Place cubed watermelon into a blender and blend until smooth. Pour the pureed watermelon through a fine mesh strainer over a large bowl or pitcher, to remove any seeds or pulp, reserving the juice.
Add the strained watermelon juice, lime juice, white wine, and orange liqueur to large pitcher. Stir to incorporate. If desired add sliced oranges, sliced limes, and blueberries, stirring to combine.
Cover and chill for 1-2 hours to allow the flavors to meld together.
Right before serving, gently stir the sangria to combine the ingredients. Serve over ice, topping with seltzer water if desired.
Garnish with fresh blueberries and watermelon stars if desired.
Notes
White Wine: Use a dry white wine like Pinot Grigio, Sauvignon Blanc, non-buttery Chardonnay, or Dry Riesling.Orange Liqueur: Triple Sec, Grand Marnier, Brandy, and Cointreau are all suitable options. Triple Sec is the most affordable option. Seltzer: Adding plain or citrus-flavored seltzer water adds a nice effervescence to this Sangria, but feel to omit it. Storage: This Watermelon Sangria will keep for 3 days in the refrigerator.