Provided is method for gravel packing dual zones within a wellbore and integrating a zonal isolation system. The method, in one embodiment, includes creating an outer sub-assembly and an inner sub-assembly, wherein the inner sub-assembly is positioned within the outer sub-assembly. The method further includes running the outer sub-assembly proximate a bottom of a downhole portion of a wellbore, and setting an uphole packer in an uphole portion of the wellbore and a downhole packer in the downhole portion of the wellbore. The method further includes gravel packing an upper zone and a lower zone, pulling the gravel pack service tool assembly out of the wellbore thereby isolating the upper zone and the lower zone from each other and the wellbore, and running an upper completion into the wellbore to open one or both of the upper zone or the lower zone for production.