The contribution of this paper is to explore how in-situ co-design of indoor spaces (e.g. building) of Location-based Mobile Games could be handle, by describing the learned lessons on this topic. This paper presents a conceptual framework for in-situ co-design of indoor spaces on Location-based Mobile Games to assist to carry out this kind of experience using useful resources (as Design Thinking’s resources). An experience of in-situ co-design for an indoor space on a Locationbased Mobile Game is presented using this framework; for some phases an authoring tool was used which allows in-situ co-design of relevant locations for an application. Based on this experience, the authoring tool was extended to create a specific kind of Location-based Mobile Game. This paper presents this extension along with a proof of concept that shows how an in-situ co-designed game created by this extension was used by end-users.