Generation of syngas from natural gas is an important process in industry, because syngas is a popular precursor for production of variety of different chemicals. Currently, syngas is produced by steam or partial oxidation reforming. Electrochemical Partial Oxidation (EPOx) is a novel process where fuels like methane and natural gas are partially oxidized under SOFC operation to co-generate electricity and syngas. In the view point of SOFC commercialization, such process could significantly off-set the manufacturing costs of SOFC generators, due to production of valuable syngas during the life of the generators. We have previously demonstrated high electrical power densities and syngas generation rates under EPOx operation using Ni-YSZ button cells. In this work, SOFCs featuring novel fuel barriers are used for EPOX operations. These SOFCs are well suited for EPOx due to their stable performances under direct hydrocarbon fueled operations and relatively high performances under intermediate temperatures. Flattened tubular design of SIS-SOFC in particular, would potentially simplify product gas collection compared to planar designs. The results on electrical tests and exhaust gas analysis using differentially pumped mass spectroscopy are presented. The effects of reforming catalysts, addition of steam or CO2 in the fuel stream are discussed. Finally the stability under long term testing is presented.