During exercises in 2012 and 2013, and an overseas deployment to Japan, the P-8 reportedly exhibited radar, sensor integration, and data transfer problems, leading to additional testing. In 2012–3, Director, Operational Test and Evaluation of the US government evaluated the P-8A Increment 1, and reported the following findings:[55]

P-8A was effective for small-area and cued ASW search, localization and attack missions, but lacked the broad-area ASW acoustic search capability of the P-3C. P-8A's Mk 54 torpedoes were of limited use against evasive targets.
P-8A was effective at ASuW search, detection and classification in all-weather at short to medium ranges for all surface vessels and at longer ranges for larger vessels.
P-8A was not effective for Intelligence, Surveillance and Reconnaissance mission due to various issues including lack of high-resolution SAR capability.
P-8A had much better range, speed, and reliability than older aircraft.[56]