Abstract: A fully internally manifolded fuel cell stack is provided by each separator plate and electrolyte in the fuel cell stack having a plurality of aligned perforations forming gas manifolds extending for the length of the cell stack. Each perforation through the separator plate is surrounded by a flattened manifold wet seal structure extending to contact the electrolytes on each face of the separator plate to form separator plate/electrolyte wet seals under cell operating conditions. Conduits through the extended manifold wet seal structure provides gas communication between one set of manifolds and the anode chambers on one face of the separator plates and conduits through the extended manifold wet seal structure on the opposite face of the separator plates provides gas communication between the other set of the manifolds and the cathode chambers on the other face of the separator plates. Extended wet seal structures formed of thin plate metal provide limited flexibility and resiliency to assure good sealing.