After the successful carbonylation of light C2-4 alkanes, we turned our attention to the activation of methane, one of the most abundantly available carbon-based feedstocks. Due to its non-polarized C-H bonds and high BDE's (i.e., 105 kcal/mol), methane is exceptionally challenging to activate at room temperature. Unfortunately, when applying our optimized reaction conditions to methane, only vague traces of methane activation could be observed. In contrast, we did observe competitive HAT activation of the reaction solvent CH3CN. While effective for the Giese-type hydromethylation, reaction modifications, such as lowering the substrate concentration and use of CD3CN as solvent, led only to small and synthetically unuseful quantitities of product. Given recent successes of halogen radical-mediated HAT transformations, we decided to change the HAT photocatalyst to cheap and abundantly available FeCl3.6H2O, functioning as a source of Clꞏ which can serve as a powerful Habstractor. To our delight, significantly higher product formation was observed using this photocatalyst, confirming that the carbonylation of methane was within reach. After some minimal reoptimization (See Supporting Information), we isolated dimethyl 2-methylsuccinate 38 in 31% yield. Importantly, the reaction could be performed in non-deuterated CH3CN at a synthetically useful concentration (0.05 M). The transformation was subsequently applied to crotonitrile (39, 33%), benzyl vinyl sulfone (40, 17%) and the acrylate of an acetyl protected sugar (41, 14%). The latter example is a testimony of the impressive selectivity that can be observed for photocatalytic methane activation in presence of more accessible H-atoms in the sugar scaffold. It should be further noted that our methane carbonylation, enables the coupling of two common C1 fragments, i.e. methane and CO, and are effectively combined into an acetyl radical C2 building block. It is further important to realize that while FeCl3 was effective to enable photocatalytic activation of methane, the decatungstate anion remains the HAT photocatalyst of choice for other alkanes. This is due to the significantly reduced selectivity and slow reaction kinetics of FeCl3 (see Supporting Information).