Scoop the flesh of the guava into a blender and pulse until the pulp is broken up and it begins to get smooth. Don't pulse it to the point where seeds start to blend.
Strain the pulp and discard the seeds.
Squeeze lime juice into the guava pulp and add the maple syrup. Stir to combine.
Divide the guava lime mix into two glasses. Add ice and seltzer and sip away!