The low temperature thermoelectric properties of hydrogen-passivated graphene-based antidot lattices are theoretically investigated. Calculations are performed using density functional theory in conjunction with the Landauer formula to obtain the ballistic transport coefficients. Antidot lattices with hexagonal, triangular and rectangular antidot shapes are studied. Methods to reduce the thermal conductance and to increase the thermoelectric power factor of such structures are studied. Our results indicate that triangular antidot lattices have the smallest thermal conductance due to longer boundaries, the smallest distance between the neighboring antidots, and the armchair edges. This structure has the largest electronic band-gap and its figure of merit is the highest among other antidots in a wide range of temperature. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.025112jes] All rights reserved.