Add the pineapple, passion fruit pulp, lime juice, agave, sea salt, and 2 cups of the water to a blender.
Blend until completely smooth.
Strain through a fine mesh sieve if you prefer a smoother agua fresca, or leave it unstrained for more texture.
Stir in the remaining 2 cups of cold water.
Taste and adjust with more agave, lime juice, or water as needed.
Serve over plenty of ice and garnish with pineapple, mint, and lime.