Four in-situ tests performed in salt caverns in France and Germany are described. The main objective of these tests was to increase our understanding of the long-term behavior of abandoned caverns. It is proven that, in the long term, when cavern brine has reached thermal equilibrium with the rock mass, pressure evolution is governed by cavern creep closure and brine micropermeation through the cavern walls. An equilibrium pressure is reached when the closure rate exactly equals the permeation rate. In the shallow caverns described in this paper, equilibrium pressure is significantly lower than geostatic pressure, ruling out any risk of fracture onset at the cavern roof. Interpretation of these tests allows salt permeability to be back-calculated.