Australian officials began talking with their US counterparts about changing the AUKUS pact around a year and a half ago, a Senate estimates hearing has heard. Discussions began early last year, culminating in an announcement last weekend that Australia would buy three second-hand Virginia-class submarines in the 2030's, rather than two second-hand and one new. The change is the most significant shift to the AUKUS 'optimal pathway' since it was announced in 2023.