We study the low‐frequency dynamical properties of correlated charge carriers in various of the quasi‐two‐dimensional organic charge‐transfer salts κ‐(BEDT‐TTF)2X by means of fluctuation (noise) spectroscopy. Close to the critical endpoint of the Mott metal‐insulator transition, a pronounced increase of the 1/f‐noise level accompanied by a substantial shift of spectral weight to low frequencies indicates a sudden increase of the time scale of the charge fluctuations. For the less correlated, more metallic materials, we find a crossover/transition from hopping transport of more‐or‐less localized carriers at elevated temperatures to a low‐temperature regime, where a metallic coupling of the layers allows for coherent interlayer transport of delocalized electrons.