The second stage of MISOMIP activities (MISOMIP2, initiated in 2019) proposes standalone ocean experiments, as well as coupled ice-shhet–ocean experiments. Previous acronyms MISMIP+ and ISOMIP+ are discontinued, and all experiments are collectively referred to as MISOMIP2. In contrast to MISOMIP1, the new experiments use realistic geometries and forcing. The main objective of MISOMIP2 is to investigate the performance of existing ocean and coupled ice-sheet–ocean models in a range of Antarctic environments, through comparisons to observational data. We will assess the status of ice-sheet–ocean modelling as a community and identify common characteristics of models that are best able to capture observed features. As models are highly tuned based on present-day data, we will also compare their sensitivity to prescribed abrupt atmospheric perturbations leading to either very warm or slightly warmer ocean conditions compared to present-day. The approach of MISOMIP2 is to welcome contributions of models as they are, including global and regional configurations, but we request standardised variables and common grids for the outputs. We target the analysis on two specific regions, the Amundsen Sea and the Weddell Sea, since they describe two different ocean environments and have been relatively well observed compared to other areas of Antarctica. An observational MIPkit synthesizing existing ocean and ice sheet observations for a common period is provided to evaluate ocean and ice sheet models in these two regions.