Speculation of a S.C5.8Dry.C5.AB class decision Collins-class submarine replacement project

the sōryū-class submarine unryū in 2014. japanese submarines had been speculated forerunner replacement project.

although german type 214 submarine has comparable range , endurance collins-class, , superior range , endurance compared sōryū-class, throughout 2014 there increasing speculation japanese design had been pre-selected collins-class replacement, leading public criticism japanese submarines did not have range or endurance australia required.

a september 2012 weapons technology swap deal , july 2014 agreement on sharing of defence technology seen preliminary steps towards australian-japanese collaboration on submarine design, or towards integrating technologies sōryū s kockums designed air-independent propulsion stirling engines , research incorporating japanese boats hydrodynamic capabilities potential sea 1000 design. advantages in such deal between nations include attention securing sea 1000 project bring japanese arms manufacturers (particularly after loosening of defence export restrictions in 2014), provision of proven high-end submarine design australian military, , improved relations, both directly , mutual allies of united states of america. however, has been noted co-operation on such major defence project high risk due japan s lack of previous arms export experience, , deal negatively impact on both nations relations china. close personal relationship between then-australian prime minister tony abbott , japanese prime minister shinzō abe had been cited factor in likeliness of such deal, although caveat change in government in either nation compromise potential deal construction, or ongoing maintenance support of submarines: australian labor party has greater interest in supporting local shipbuilding abbott s coalition government, while souring of china-japan relations democratic party of japan less risk liberal democratic government led abe.

by november 2014, initial capabilities had not been decided on, , recommendations made across 2015. in december 2014, australian coalition government ruled out using tender process identify new submarine design, blaming limited time left before collins-class scheduled begin leaving service. although there speculation @ time australian government purchase directly japanese shipbuilders, in january 2015, defence minister kevin andrews stated government still considering options offered european shipbuilders: thyssenkrupp marine systems of germany, saab of sweden, , partnership of french companies thales , dcns.

in mid-december 2015, japanese self defence force allowed journalist australian broadcasting corporation (abc) tour newest of class, kokuryū (black dragon), @ base @ yokoska , speak commanding officer, commander takehiko hirama, , several other personnel.