The simulation software for ANYmal enables researchers to validate new approaches and concepts in a fast, flexible, and safe way. The simulation framework builds up on Gazebo and is fully ROS-compatible. It reflects the real robot as close as possible and includes the simulation of the state estimator, perception sensors, mapping, and localization. This way, researchers can develop complex and integrative algorithms and can directly run their work on the real ANYmal robot. Furthermore, the ANYmal simulation features a rich set of user interfaces and visualization, logging, and debugging tools.