The orientational dynamics of C-(x) in superconducting K3Ba3C60 are studied by neutron inelastic scattering. Low-energy excitations are present near similar to 6 meV between 150 and 320 K and are assigned to small-amplitude librations of the C-60(9-) ions. They are harder and broader than those measured in K3C60. reflecting the existence of a stronger and more anisotropic orientational potential. The anisotropy and dispersion effects are also larger than those in isostructural Rb6C60, as. a result of positional disorder of the Ba2+ and K+ ions. which reside in distorted tetrahedral interstices. The estimated barrier of the hindrance potential, E-a, is similar to 1.4 eV.