Before the advent of underwater maintenance procedures, it was necessary to drain a vessel in order to perform coatings maintenance. This often resulted in extended outage schedules, increased radiation exposure, and damage to otherwise sound coatings. Techniques have been developed that permit detailed inspection and effective repair without the need to drain-down. Using these techniques, it is possible to significantly extend the service-life of coatings in immersion service. This chapter covers the development, implementation, and execution of an underwater coatings maintenance program. Topics covered include cleaning, inspection, and coating repair. For example, in a suppression pool, the vessel shell and internals, including strainers, are cleaned using an underwater vacuum system operated by divers. As the shell is cleaned, divers can inspect and document 100 % of the underwater surfaces. Inspections that meet IWE and maintenance rule requirements are possible. Following inspection, coating defects can be identified and repaired using a 100 % solids underwater cured epoxy.