Infrared photodissociation (IRPD) spectra of M+(H2O)(n)Ar (M = Rb, Cs; n = 3-5) with simultaneous monitoring of [Ar] and [Ar+H2O] fragmentation channels are reported. The comparison between the spectral features in the two channels and corresponding energy analysis provide spectral assignments of the stable structural conformers and insight into the competition between ion-water electrostatic and water-water hydrogen bonding interactions. Results show that as the level of hydration increases, the water-water interaction exhibits the tendency to dominate over the ion-water interaction. Cyclic water tetramer and water pentamer substructures appear in Cs+(H2O)(4)Ar and Cs+(H2O)(5)Ar systems, respectively. However, cyclic water tetramer and pentamer structures were not observed for Rb+(H2O)(4)Ar and Rb+(H2O)(5)Ar systems, respectively, due to the stronger influence of the rubidium ion-water electrostatic interaction. The energy analysis, including the available internal energy and the IR photon energy, helped provide an experimental estimate of water binding energies.