The martensitic transformation of austenite as well as the reversion of martensite to austenite has been reported to significantly improve mechanical properties of steels. In the present work, three dimensional (3D) elastoplastic phase-field simulations are performed to study the kinetics of martensite reversion in stainless steels at different annealing temperatures. The input simulation data are acquired from different sources, such as CALPHAD, ab initio calculations, and experiments. The results show that the reversion occurs both at the lath boundaries as well as within the martensitic laths, which is in good agreement with the experimental observations. The reversion that occurs within the laths leads to splitting of a single martensite lath into two laths, separated by austenite. The results indicate that the reversed austenite retains a large extent of plasticity inherited from martensite.