Following the current trend towards the space exploration, this study focuses mainly on the conceptualisation of the most efficient lunar arch forms to be adopted by the future structural designers. More specifically, the static behaviour of varying-thickness arches (VTAs) produced by an iterative form-finding algorithm against constant-thickness arches (CTAs) is examined herein. These optimised arches are assumed to be constructed by laser-sintered additive manufactured lunar regolith, following a 3D-printing technique. The paper initiates with finite element analysis (FEA) of both VTAs and CTAs where it is witnessed that VTAs need to be geometrically enhanced, by means of thickening certain weak/narrow parts of their cross-section, in order to minimise the principal compressive and tensile stresses and the amount of strain energy exhibited locally. The work concludes with the quantification of the efficiency of the enhanced VTA shapes over the typical CTAs in lunar gravitational environments.