Water-flooding aided by electromagnetic (EM) heating using microwaves (MW) has a great potential for heavy oil recovery. Earlier, we have shown experimentally and theoretically that EM radioactive energy is absorbed by water and converted into heat near the EM source. The heat is imparted into the oil phase while being transported deep into the porous medium (Paz et al. in Transp Porous Media 119(1):57–75, 2017). The lowering of water is primarily responsible for the improved oil recovery in this process. This paper develops a model describing electromagnetic heating-assisted water flooding (EMA WF) in a thin heavy oil reservoir. The model is solved numerically using a staggered algorithm joining Galerkin Least Square Finite Elements Method (GLS-FEM) and Kurganov–Tadmor Finite Volumes Method (KT-FVM). Numerical results were obtained for different types of oil. For the considered parameter values, the EM heating technique increments the oil production up to 56% after a 24-month injection. This increment is inversely proportional to the oils API gravity. The implementation was validated by comparing computational results with the simplified model’s analytical solution obtained using Conservation Laws theory and the Sturm–Liouville theory. Simple convergence analysis was also performed endorsing our numerical approach. Both analytical and numerical approaches were obtained for the two-dimensional geometry with two parallel horizontal wells. The temperature profile obtained through the simplified model’s analytical solution is close to the one obtained by simulations (less than 1.9% relative error).@en