Cratons are stable parts of the Earth’s continental lithosphere that have remained largely undeformed for several billion years. These consist of crustal granite-greenstone terrains coupled to roots of strong, buoyant cratonic lithospheric mantle that extend up to several hundreds of kms depth. Due to their stability, cratons preserve a record of the tectonics and the thermal evolution of the mantle in the early Earth. These observations suggest that the highly viscous (strong) character of cratons hampered the viability of early Earth tectonics, thereby affecting mantle convection patterns and cooling. In this study, we investigate the controls of stiff cratons on the initiation of subduction and mantle thermal evolution on the early Earth. Using numerical models, we simulate the effects of strong and buoyant cratons on mantle convection. We vary a set of parameters including (i) width and thickness of cratons, and (ii) viscosity ratio between cratonic lithosphere and cratonic crust. We test initial conditions varying the number of cratons, which is unconstrained for early Earth and associated it to mantle cooling rates. Our preliminary results show that the mantle cooling rate decreases with increasing number of cratons. Because mantle cooling rates affect the early Earth transition from a basaltic drip regime to initiation of subduction, we show that the craton coverage on the early Earth controls the time of onset of plate tectonics. Furthermore, we observe that cratons will remain separate or combine depending on the convective cell size, which is function of mantle cooling.