This paper seeks to consider how issues of environment, realism and ideas of physical and virtual space are influencing developments in AR within the context of heritage sites. It considers the technical challenges that AR applications face at these sites such as; high computational demands, remote locations, scene detection and tracking, and the difficulty of virtually duplicating real-world environmental conditions convincingly. These technical innovations create a framework for all other aspects of the application, particularly in how we develop engaging user experiences, and facilitate new forms of interaction that look towards more performative and experiential forms of interpretation. This paper looks at how the nature of AR offers opportunities to negotiate contemporary ideas of space in these sites and ways to explore them. Drawing upon examples of the technical challenges AR faces, the paper aims to demonstrate the crucial impact this can have on user experience and the design of interactions. The academic definitions of ‘presence’ sought within mediated interactions no longer fit these developing uses of AR. As such, the paper calls for more exploration of the term, one that fits the nuanced forms of engagement and embodied experiences of cultural material being fostered.