This data set contains experimental and numerical data from a 12x12 wire-mesh sensor. A 12x12 WMS was used to measure paraffin phantoms created to mimic three flow patterns: slug, annular and bubble flow. The sensor was assembled with flanges and filled with tap water. Two models based on finite element model were used to generate the synthetic data. The first one is a basic FEM model, which was designed based on other models reported in the literature (i.e. the output signal is obtained by integrating the current density over the surface of a receiver wire). In the second model (FEM+EC), the electric potential is solved as the basic one, however, external circuits (macromodels) were coupled to the 3D geometry of the sensor to emulate the excitation and amplification systems of a real WMS.A mapping containing the coordinates and electrical properties of the paraffin phantoms was created through image processing and imported into the software COMSOL v.5.6. Thus, both basic FEM and FEM+EC models were used to generate synthetic data that can be direct compared to the experimental data.