Axis codebreaking was uneven but consequential

Did the Axis navies achieve notable codebreaking successes?

Yes. Italy had capable codebreakers, Germany achieved successes against Soviet systems, and Japanese intelligence gains helped its opening operations.

Italian codebreaking was capable, while German results were less consistent and included successes against Soviet systems. Japanese intelligence understood more about its opponents than is often assumed. Intelligence gains before 1941 helped Japan know what it would face in the opening operations, contributing to their success.