Scattering of surface waves by two permeable vertical walls having apertures at different depths in uniform finite depth water has been studied assuming linear theory. The problem is reduced to a set of coupled integral equations involving the difference of velocity potentials across each wall as unknown function. A multi-term Galerkin's technique is employed to approximate these unknown functions and to obtain approximate solution of the integral equations. Numerical estimates for the reflection and transmission coefficients are then obtained by solving a linear system. It is observed from graphical representations of the reflection coefficient that in comparison with non-identical walls the minima of the reflection coefficient become very close to zero at discrete frequencies in case of identical walls. Very good agreement between some earlier known results and our present results is established. © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group.