This bulletin provides a snapshot of the sale and distribution of fentanyl and its analogues across several popular illicit darknet markets. Data collected daily from six darknet markets between 2 January and 23 February 2019 reveal the amount, types and physical forms of fentanyl available. Of more than 123,000 unique drug listings identified, nearly 7,400 were opioids, of which 439 (0.347% of all drugs listed) were fentanyl products. Between 15 and 22 kilograms of fentanyl was available on any day and the average price per gram varied between A$30 and A$301, depending on the physical form. The data also reveal the shipping methods, cross-market operations and product specialisation of the 102 active fentanyl vendors on these six darknet markets.