The Drug Use Monitoring in Australia program involves the routine collection of survey and urinalysis data from police detainees across Australia. In 2020, almost half of the detainees reported using cannabis (47%) and methamphetamine (45%) in the past 30 days. Fewer detainees reported using benzodiazepines (21%), cocaine (8%), heroin (7%) or ecstasy (5%) in the past month. In the early stages of the COVID-19 pandemic, the availability and quality of methamphetamine and heroin declined. Past-month methamphetamine use, as confirmed by urinalysis results, also decreased from 55 percent in January–February to 38 percent in April–June.