Confined water presents unusual properties in comparison with other sorbate species. First of all, the sorption isotherm is of type III, even in the microporous confinement range (Ø < 20 Å). Whatever the pore diameter, water sorption phenomenon looks like the so-called capillary condensation phase transition. Our results clearly valid such an expected behaviour in the mesoporous confinement range (20 Å < Ø < 40 Å). The water confined phase is a liquid phase characterized by a short range order and a high translational molecular mobility. The confinement induces a strong displacement towards the low temperature of the water confined liquid solidification T sol. (for instance, T sol. = 230 K for D2O confined liquid in MCM-41 (Ø = 24 Å). We have determined the structure of the water confined solid phase observed below T sol.. It looks like those of the cubic ice structure affected by strong quasi-isotropic finite size effects induced by the confinement. Such a quasi-(1d) solid appears as a polycrystalline column rather than a single crystalline nanofiber. Concerning water confinement in the microporous range (as for example, AlPO4-5 zeolite (Ø = 7.3 Å)), our results are more surprising. Type III sorption isotherm is the signature of a crystallization phenomenon at room temperature (T = 300 K). The confined water crystallizes in two helices that are commensurate with the AlPO4-5 micropore structure. The confined ice has a density of 1.2 g⋅ cm− 3.