Advances in internetworking technology and the decreasing cost-performance ratio of commodity computing components have enabled Volunteer Computing (VC). VC platforms aggregate tens or hundreds of thousands of hosts. These hosts are typically volatile, which raises di cult research questions. Most research in this area relies on simulation. The main issue when developing VC simulators is scalability: How to perform simulations of large-scale VC platforms with reasonable amounts of memory and reasonably fast? To achieve scalability, state-of-the-art VC simulators employ simplistic simulation models and/or target on narrow platform and application scenarios. In this paper we enable VC simulations using the general-purpose SimGrid simulation framework, which provides signi cantly more realistic and exible simulation capabilities than the aforementioned simulators. Our key contribution is a set of improvements to SimGrid so that it brings these bene ts to VC simulations while achieving good scalability.