Down Under for Aground is a quality-of-life mod designed for players looking to expand their building capabilities in the game. This mod allows players to construct essential structures beneath the surface, provided they have the appropriate blueprints. Versionof the mod, released on August 20, 2019, introduces a streamlined approach to underground and underwater construction, enhancing gameplay flexibility and creativity.

The mod does exclude certain structures for compatibility reasons, such as airports and space structures, while allowing upgrades to existing buildings anywhere. Players can refer to provided lists for guidance on which structures can be placed underground or underwater. The Down Under mod ultimately enriches the Aground experience by offering new building options that promote exploration and resource management.