The title compound, mu-6,9-chloro-8-methoxy-6,9-bis(eta5-pentamethylcyclopentadienyl)-6,9-dirhoda-5-thia-arachno-decaborane(7), [Rh2(CH10B7OS)(C10H15)2Cl], has a single Cl atom bridging the two remote rhodium 'prow' vertices of an arachno ten-vertex dirhodathiadecaborane cluster, with Rh-Cl distances of 2.3475 (11) and 2.3536 (11) A, and an Rh-Cl-Rh angle of 106.82 (4) degrees.