The proposed new CCP-WSI+ builds on the impact generated by the Collaborative Computational Project in Wave Structure Interaction (CCP-WSI) and extends it to connect together previously separate communities in computational fluid dynamics (CFD) and computational structural mechanics (CSM). The new CCP-WSI+ collaboration builds on the NWT, will accelerate the development of Fully Coupled Wave Structure Interaction (FCWSI) modelling suitable for dealing with the latest challenges in offshore and coastal engineering. Since being established in 2015, CCP-WSI has provided strategic leadership for the WSI community, and has been successful in generating impact in: Strategy setting, Contributions to knowledge, and Strategic software development and support. The existing CCP-WSI network has identified priorities for WSI code development through industry focus group workshops; it has advanced understanding of the applicability and reliability of WSI through an internationally recognised Blind Test series; and supported collaborative code development. Acceleration of the offshore renewable energy sector and protection of coastal communities are strategic priorities for the UK and involve complex WSI challenges. Designers need computational tools that can deal with complex environmental load conditions and complex structures with confidence in their reliability and appropriate use. Computational tools are essential for design and assessment within these priority areas and there is a need for continued support of their development, appropriate utilisation and implementation to take advantage of recent advances in HPC architecture. Both the CFD and CSM communities have similar challenges in needing computationally efficient code development suitable for simulations of design cases of greater and greater complexity and scale. Many different codes are available commercially and are developed in academia, but there remains considerable uncertainty in the reliability of their use in different applications and of independent qualitative measures of the quality of a simulation. One of the novelties of this CCP is that in addition to considering the interface between fluids and structures from a computational perspective, we propose to bring together the two UK expert communities who are leading developments in those respective fields. The motivation is to develop FCWSI software, which couples the best in class CFD tools with the most recent innovations in computational solid mechanics. Due to the complexity of both fields, this would not be achievable without interdisciplinary collaboration and co-design of FCWSI software. The CCP-WSI+ will bring the CFD and CSM communities together through a series of networking events and industry workshops designed to share good practice and exchange advances across disciplines and to develop the roadmap for the next generation of FCWSI tools. Training and workshops will support the co-creation of code coupling methodologies and libraries to support the range of CFD codes used in an open source environment for community use and to aid parallel implementation. The CCP-WSI+ will carry out a software audit on WSI codes and the data repository and website will be extended and enhanced with database visualisation and archiving to allow for contributions from the expanded community. Code developments will be supported through provision and management of the code repository, user support and training in software engineering and best practice for coupling and parallelisation. By bringing together two communities of researchers who are independently investigating new computational methods for fluids and structures, we believe we will be able to co-design the next generation of FCWSI tools with realism both in the flow physics and the structural response, and in this way, will unlock new complex applications in ocean and coastal engineering