Super city amalgamations are cast as a contemporary solution to the challenges of planning across borders. In 2010, Auckland was ‘super-sized’ into a unitary metropolitan authority to govern, plan, and manage the metropolitan city region. We argue that this super-sizing comprises a mode of ‘governance by re-bordering’, in which urban problems are framed and solved through techniques of territorial restructuring and strategic coordination. This article examines the re-bordering of local government municipalities into super cities and analyses the subsequent implications for planning, policy, and community drawing on the cases of Auckland, Brisbane/SEQ, and Vancouver. Due attention is given to the planning challenges arising from super amalgamations that rescale central-local government relationships; reassert local government roles in promoting efficient and coordinated spatial planning; and reform the collaborative urbanism in a regional mode of political action.