They also recovered €8 million in cash.
Drugs valued at a combined €36 million were seized by Gardai last year.
The Garda Annual Report shows almost €8 million in cash was also recovered by the Garda National Drugs and Organised Crime Bureau.
Officers made almost 23,000 contacts with domestic abuse victims in 2020, and Garda negotiators dealt with 93 hostage and barricade incidents.
Last year also saw the number of Gardai reach its highest level in the history of the State, with the figure now standing at 14,491.