The Monte Carlo classical trajectory method is used to study collisions of alkali ions I+ with H2O and D2O. Formation of the vibrationally excited intermediates I+ (H2O)* and I+ (D2O)* requires energy transfer from relative translation to the water molecule's vibrational and rotational degrees of freedom. This energy transfer probability is inefficient and decreases exponentially with increase in relative translational energy nearly independent of the initial impact parameter. The energy transfer probability is strongly dependent upon the alkali ion, but only has small variations between H 2O and D2O. The inefficient energy transfer manifests itself kinetically in recrossing of the dividing surface separating the hydrated ion and the two reactants. As a result, the bimolecular rate constant for hydrated ion formation is smaller than that predicted by variational transition state theory. Several different statistical and collision theories are compared, and it is found that an activated complex theory expression for the bimolecular rate constant can be derived within the framework of collision theory and the average molecular interaction (AMI).