Transport of subtropical waters in the Japan Sea is simulated based on altimeter data. Preferred transport pathways across the Subpolar Front are found. The cross-frontal transport is shown to be inhomogeneous with gates and barriers whose locations are determined by a local velocity field. The gates open due to suitable dispositions of mesoscale eddies facilitating propagation of subtropical waters to the north. There are forbidden zones where the northward transport has not been observed.