This study assessed the longitudinal costs of offender trajectories in Queensland (Australia) to provide policymakers with evidence that could be used to promote the use of crime prevention programs. Few studies have assessed these costs and minimal research has been conducted outside the United States. The study addressed three research questions: (1) What are the monetary costs of crime? (2) What is the optimal number of offender trajectories in an Australian offender cohort? and (3) What are the monetary costs of officially recorded offending for individuals on different offender trajectories? The Semi-Parametric Group-based Method (SPGM) was used to determine the number of offender trajectories in the Queensland Longitudinal Database. This database included 41,377 individuals who were born in 1983 and 1984 and guilty of offences in Queensland that were committed when aged 10–25 years old. The costs of crime were assessed using two approaches. First, criminal justice system costs were estimated based on the number and type of contacts that individuals had with the criminal justice system as well as the length of any supervision served. Second, wider social and economic costs were assessed based on offence type. Results indicated that there were five offender trajectories, including two chronic, one moderate and two low trajectories. When costs were applied to the offender trajectories, offenders in the two chronic groups were 4.8% of the cohort but accounted for 41.1% of the total costs. On average, each chronic offender cost between $186,366 and $262,799 by the time they turned 26 years old, with 60% of the costs accounted for by the criminal justice system. On average, each chronic offender cost over 20 times more than offenders in the two low offending groups. These findings provide further evidence for the potential benefits of implementing interventions that target chronic offenders.