This study uses data from the Drug Use Monitoring in Australia program to examine the impact of the COVID-19 pandemic on cannabis demand and supply in Australia. It found past-month cannabis users reported using cannabis on a median of 25 days per month, significantly more often than before the pandemic. Those experiencing changes in their employment, financial or living situation or mental health or who used drugs to cope with negative emotions were more likely to increase cannabis use. Most users reported no changes in cannabis supply, but there were increasing prices and decreasing numbers of dealers in Brisbane.