The porous structure of Bowen Basin coal macerals is very important in the storage and transport of coal seam gases. As part of a full characterization of this porosity, several coal macerals were examined by atomic force microscopy. Mesopores of greater than or equal to 8 nm deriving from different types of porosity were imaged. The pores were either formed by contact points between spherical clusters of molecules or were defined channels that had been created by some physical process. The potential of this technique for characterizing the porous structure in greater depth was demonstrated.