This paper presents a parallel computing scheme for the data computation that arise when applying one of the most popular electromagnetic methods in exploration geophysics, namely, controlled-source electromagnetic (CSEM). The computational approach is based on linear edge finite element method in 3D isotropic domains. The total electromagnetic field is decomposed into primary and secondary electromagnetic field. The primary field is calculated analytically using an horizontal layered-earth model and the secondary field is discretized by linear edge finite element method. We pre-calculated the primary field through of an embarrassingly-parallel framework in order to exploit the parallelism and the advantages of geometric flexibility. The numerical-computational formulation presented here is able to work with three different orientations for the dipole or excitation source. Our code is implemented on unstructured tetrahedral meshes because are able to represent complex geological structures and they allow local refinement in order to improve the solution’s accuracy. The code’s performance is studied through a test of scalability.