One-electron oxidation of a stable tris[di-tert-butyl(methyl)silyl]silyl radical by the triphenylmethylium ion produces the corresponding silylium ion 2. However, this underwent a rapid intramolecular methyl group migration to form a more stable silylium ion 4 via a Wagner-Meerwein type rearrangement. The facile 1,3-methyl migration over the three peripheral silicon atoms in 4 was observed in NMR time scale.