We investigate small scale equidistribution of random orthonormal bases of eigenfunctions (i.e. eigenbases) on a compact manifold M. Assume that the group of isometries acts transitively on M and the multiplicity m λ of eigenfrequency λ tends to infinity at least logarithmically as λ → ∞. We prove that, with respect to the natural probability measure on the space of eigenbases, almost surely a random eigenbasis is equidistributed at small scales; furthermore, the scales depend on the growth rate of m λ . In particular, this implies that almost surely random eigenbases on the sphere S n (n ≥ 2) and the tori T n (n ≥ 5) are equidistributed at polynomial scales.2010 Mathematics Subject Classification. 58G25, 58J65, 35P20, 60B10.