The Australian Community Climate and Earth System Simulator, ACCESS, is Australia’s national modelling system for all timescales from weather forecasting to climate projections. ACCESS is a family of related models, configured for specific applications, to meet operational and research needs. ACCESS is built from core component models: the UK Met Office Unified Model (UM) for the atmosphere, the Community Atmosphere Biosphere Land Exchange (CABLE) model for the land, the US NOAA/GFDL Modular Ocean Model (MOM) for the ocean and the LANL CICE model for sea ice. Additional modules support biogeochemistry and atmospheric chemistry. Different ACCESS model configurations may use a subset of the core models for atmosphere-only or ocean-only simulations or may replace component models to meet the needs of a specific application. This special issue brings together papers that describe ACCESS model configurations and code development, as well as papers that evaluate the performance of the model across any ACCESS application.