The Coast Guard has undertaken a project to modernize information technology onboard certain ships and aircraft. This technology is referred to collectively as Command, Control, Communication, Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR) systems. The C4ISR project is a major information technology investment with an acquisition life cycle cost of $1.5 billion through fiscal year 2026. The Coast Guard has implemented information technology systems that effectively support the mission needs of some ships and aircraft. Specifically, the systems have met overall performance requirements and have improved operational capabilities, including increased situational awareness, better communication within the Coast Guard and with its partners, and enhanced sensor capabilities. The Coast Guard, however, has not carried out some planned system enhancements that were necessary to support mission needs of certain aircraft and legacy ships. These enhancements were not carried out because of significant budget reductions. Revised plans do not fully address how the Coast Guard will meet the critical technology needs of these aircraft and legacy ships. As a result, these ships and aircraft continue to rely on obsolete technology which impacts mission performance and makes operations and maintenance more difficult and costly.