The appealing hypothesis of thermally produced dark matter frequently meets strong constraints from direct detection. Consequently, dark sectors with small couplings to the Standard Model are experimentally motivated. In the very weakly-interacting regime new processes, such as co-scattering, set the relic abundance. The distinctive feature of this regime is the suppressed decays of mediators. Interestingly, they appear to be long-lived also at collider scales, leading to signatures with displaced particles. Using the higgs portal as a benchmark scenario, I will discuss the phenomenology of this correspondence between the decoupling regimes and the experimental signals.