One of the most promising corners in which new physics could be hiding at the Large Hadron Collider is in long-lived signatures. New, fundamental particles with measurably long lifetimes are predicted by many models of new physics, including supersymmetry and hidden valley models. Dedicated searches are required to look for the unusual and challenging detector signatures produced by new, long-lived particles. In this talk, I will present an overview of the searches for long-lived supersymmetric particles performed by the ATLAS experiment, with a focus on recent results. I will discuss the interplay between the detector design and its sensitivity to long-lived particles, and I will present the plans for an upgrade to the ATLAS inner tracker and highlight how the new tracker will present new challenges and opportunities for these searches.