New sub-µs isomers have been observed in the neutron-rich Sn isotopes. 125,127,129 Sn nuclei have been produced in a relativistic fission reaction of 238 U on a 9 Be target at 750 A·MeV and by the fragmentation of 136 Xe at 600 A·MeV populating high-spin yrast states. In addition to the already known µs isomers, three new ones with sub-µs half-lives have been observed. These yrast isomers are the high-spin members of the ν(d −1 3/2 h −2 11/2 ) and νh −n 11/2 , seniority v = 3 multiplets leading to isomeric (23/2 + ) and (27/2 − ) states, respectively. Added to the already known 19/2 + µs isomers in this region the current work completes the systematic information of neutron-hole excitations toward the filling of the last h 11/2 orbital at N = 82. The results are discussed in the framework of state-of-the-art shell-model calculations using realistic interactions.