In this article, we thoroughly describe and evaluate an innovative software platform for documenting an excavation of an archaeological site and the use of its findings in creating augmented and mixed reality educational applications. The excavation that contributed to the design of the platform and showcased its functionality is that of the archaeological site at the Sanctuary of Apollon in Amykles (Sparta, Greece). For the 3D mapping of the site and the 3D modeling of the structure of the findings, motion photogrammetry software was used including processing of terrestrial photos, aerial photos, and total station data. The platform consists of three systems, namely a central documentation platform (CDP) that support 3D, a system for creating educational narrative applications (END) in AR, and a system for creating mixed reality training modules (MRT). The development of a focused metadata scheme that supported the three systems of the platform played a significant role in the coherence and usage of the information and insights obtained by the 3D models and the archaeological documentation. The demonstration and evaluation of the platform that we present here show that it facilitates improvements in the workflow from the 3D digitization and documentation of an excavation to the exploitation of the findings and the entire excavation procedure through an educational approach utilizing AR and MR technologies.