Sc5Rh6Sn18 is a diamagnetic metallic compound (space group: I 41/a c d , a ≈13.5 Å , c ≈27.1 Å ) which becomes superconducting (sc) at Tc=5.15 K . The sc state was studied on single-crystal samples by temperature- and field-dependent electrical resistivity, specific heat, and muon-spin rotation (μ SR ) spectroscopy. No anisotropy of the upper critical field Bc 2=7.75 T is observed. Analyses of specific heat indicate enhanced values of the jump [∆ cp/(γtotTc) =1.58 ] and of the energy gap ratio [∆ (0 ) /(kBTc) =2.39 ] as well as an exponential decrease of the electronic contribution below Tc/2 . Together with the saturation of the superfluid density for T <3 K observed by μ SR spectroscopy these findings lead us to classify Sc5Rh6Sn18 as a moderately strong coupled isotropic s -wave superconductor. However, above Tc, the crystals reveal a surprisingly anisotropic and large resistivity of 2.5 -4.5 m Ω m with metalliclike behavior perpendicular to the c axis and by a factor of ∼2 larger parallel to c , which decreases upon increasing temperature. These observations are discussed in connection to a characteristic intrinsic disorder in the crystal structure of Sc5Rh6Sn18 .