Carbon reduction targets are becoming increasingly common features of firms’ climate commitments. However, questions remain about their ambition, coverage, and credibility. This paper presents the first comprehensive descriptive analysis of carbon targets disclosed by ASX300 firms. We utilise novel data from the LSEG Climate MAP database on emissions reduction targets set by ASX300 firms between 2018–2024 to provide insights on target adoption, ambition, progress against targets and accompanying internal climate governance. We document that target-setting activity has increased rapidly over time. Targets have also become significantly more ambitious on average, with rapidly growing prevalence of net-zero targets. However, most firm-year observations lack an active target, most active targets only cover Scope 1 and 2 emissions and only some cover Scope 3, and, while ambition has increased, average target progress has stalled, and most firms are not on track to meet linear decarbonisation trajectories. Moreover, we show that for a number of firms, carbon credit purchase significantly inflates reported target progress. Target adoption, ambition, and performance also vary substantially across sectors. Overall, our findings highlight a growing gap between stated climate ambition and realised emissions reductions in corporate Australia. The results have important implications for policymakers, investors, and standard setters as Australia transitions from voluntary climate disclosure to a mandatory, assurance-based reporting regime.