Abstract Wavy type Single Chamber Solid Oxide Fuel Cells (SC-SOFCs) are beneficial for improved triple phase boundary conditions contributing to higher performance, compared with planar type SC-SOFCs of the same diameter. This study presents a fabrication process for wavy-type, cathode-supported SC-SOFCs with a single fabrication step via co-sintering of a triple-layer structure consisting of NiO/CGO-CGO-LSCF, with a thickness ratio of 1:3:9 respectively. Curvature evolution occurs due to different sintering behaviour of each layer during the co-sintering process. In-situ observation of each layer during the co-sintering process allows for minimisation of mismatched stresses to avoid unnecessary warping and cracking. Bilayers, consisting of NiO/CGO-CGO and CGO-LSCF, are co-sintered at 1200 °C. In-situ observation, to monitor the shrinkage of each material and the curvature evolution of the structures, is performed using a long focus microscope (Infinity K-2). Monitoring curvature behaviour in real time minimised the development of undesired curvature in the triple-layer structure. Performance testing of wavy cell is carried out in a methane-air mixture (CH4:O2 = 1:1). The wavy SC-SOFC generated 0.39 V and 9.7 mW cm−2 at 600 °C, which produced 260% and 540% increments in OCV and in maximum power density, respectively, over the planar SC-SOFC under the same operational conditions.