The operation, which mainly occurred in the US and Europe and included four arrests in the UK, came more than a year after officials took down the so-called Wall Street Market, believed to have been one of the largest illegal online marketplaces on the darknet.
The darknet is a part of the internet hosted within an encrypted network and accessible only through specialised anonymity-providing tools, most notably the Tor browser.
Law enforcement seized cash and virtual currency as well as 500kg of drugs, the Justice Department said.
About 275kg of drugs, including fentanyl, heroin, cocaine, ecstasy and other opioids, were seized in the US.
The arrests included 121 in the US, two in Canada, 42 in Germany, eight in the Netherlands, four in the UK, three in Australia and one in Sweden.
The US Justice Department said its investigation was continuing and investigators were still working to identify other individuals behind darknet accounts.
Deputy attorney general Jeffrey Rosen said the operation showed “there will be no safe haven for drug dealing in cyberspace”.
