The ability to make payments offline means being able to use a CBDC without being connected to the internet, either temporarily or because of coverage limitations. Central banks considering the potential implementation of CBDCs with offline functionality must take into account a complex matrix of issues including security, privacy, likely risks, the types of solution, their maturity and applicability, and operational factors. The handbook, compiled in partnership with Consult Hyperion, addresses these issues as well as objectives for resilience, inclusion, cash resemblance, accessibility and other desired attributes. The degree to which CBDCs will be provided or used offline will vary significantly by country, region, demographics and specific contexts, which will also influence the solutions chosen. CBDC systems, like all digital payment systems, must work for everyone in society, whenever and wherever individuals and businesses need them. The ability to pay when offline could ensure this is achieved by providing a layer of resilience, as well as supporting inclusion, accessibility and privacy objectives. Implementing offline payment capabilities will require a deeper understanding of the technologies, security threats, risks and mitigating measures, as well as design criteria for privacy, inclusion and resilience. This handbook is intended as a guide to central banks starting this work. Beju Shah, Head of the BIS Innovation Hub Nordic Centre Over several workstreams, Project Polaris will provide central banks with the essential information needed to inform decision-making, architecture, design, implementation planning and investments. It will also address long-term change and operational considerations.