The peculiar purpose and population of the Australian penal colonies presented a raft of problems for the administration of justice and the maintenance of discipline. There was a perceived need for a simplified and more coercive system of law, which however coincided with a desire that local law and justice be fairly applied and keep pace with metropolitan legal reforms. That bred numerous tensions and confusions. This chapter considers how the need to control convict populations in colonial New South Wales and Van Diemen’s Land invited a myriad of compromises and peculiarities, including a chaotic application of English transportation law and the assumption of vast and informal powers by colonial magistrates. Although there was a broad shift over time towards the normalising of colonial justice and discipline, the imperial and local governments were slow to correct local informalities, injustices, and deviations from metropolitan law and practice.