The involvement of lattice oxygen species is important toward oxidative coupling of the methane reaction (OCM) over supported Mn-Na2WO4/SiO2 catalysts, but there is no consensus regarding the types, role, and origin of lattice oxygen species present in supported Mn-Na2WO4/SiO2 catalysts, which hinders the understanding of the OCM reaction network. In the present study, by utilizing the temporal analysis of products technique, we show that supported Na2WO4/SiO2 catalysts possess two different types of oxygen species, dissolved O2 and atomic O, at an OCM-relevant temperature. The addition of Mn-oxide to this catalyst increases the total amount and release rate of dissolved O2 species and improves C2 selectivity of both dissolved O2 and atomic lattice O species.