The mobility of water molecules and deuterons of the deuterated analogue of solid 12-tungstophosphoric acid, H3PW12O40.nH(2)O (HPA) (n = 5.5 and 0.1), has been characterized by deuterium solid-state NMR. Analysis of the H-2 NMR line shape and spin-lattice relaxation times allowed us to characterize the deuteron and water dynamics in HPA, at different water contents, in the temperature range 103-383 K. At 163-193 K and for n = 5.5, an intramolecular motion corresponding to reorientations by 1800 flips around the C-2 axis of water in the [D5O2](+) ion has been detected, the deuteron being probably immobile. At temperatures above 313 K, both water and deuteron become involved in fast rotation around the C-3 axis of the formed [D3O](+) ion. The rotation is performed on a time scale of 30-50 ns with an activation energy E-a of 8.5 kJ/mol. For n = 0.1, three dynamically different species can be distinguished: mobile deuterons, mobile [D3O](+) ions, and immobile deuterons. Mobile deuterons are weakly bonded to polyanions and move fast with a characteristic time of a few picoseconds and E-a = 8.6 kJ/mol. [D3O](+) ions move more slowly than deuterons, but still fast, with a time scale of a few nanoseconds, and E-a = 17.6 kJ/mol. The characteristic time for immobile deuterons is much greater than a few microseconds.