A method for switching between access methods while a data set is open includes attempting, on behalf of a first system, to gain access to a data set. The method further determines whether the data set is already open by a second system. In the event the data set is already open, the method uses a first access method to access the data set. In the event the data set is not already open, the method uses a second access method to access the data set. In certain embodiments, the first access method is an RLS (Record Level Sharing) access method and the second access method is a base VSAM (Virtual Storage Access Method) access method. A corresponding system and computer program product are also disclosed.