OLCF’s Center for Accelerated Application Readiness (CAAR) was created to ready applications for the facility’s next-generation supercomputers. CAAR is a partnership of the SciComp group, scientific application teams, vendor partners, and tools developers to ensure that users can make the most of the OLCF’s newest supercomputing systems on day one and get the most science out of their allocations. Through CAAR, codes teams gain access to early software development systems, leadership computing resources, and technical support in the development years leading up to the launch of a new supercomputer. The program culminates with each team’s scientific grand-challenge demonstration on the machine. The suite of CAAR applications covers a broad range of scientific disciplines and employs a range of programming models and software designs.