The Naval Service, together with An Garda Síochána and the Customs Service of the Revenue Commissioners form the Joint Task Force on Drug Interdiction with responsibility for the interdiction of illegal narcotics at sea.

Compulsory random drug testing & targeted drug testing:
In 2015, the Defence Forces drug testing team carried out 13 drug testing operations, testing a total of 1,184 Defence Forces personnel. Of the 1,184 tests, 98.56% proved negative. There were 17 positive tests representing 1.44% of the total tests completed. Appropriate administrative action ensued in all cases. As of 31st December 2015, two members of the Defence Forces were subject to targeted drugs testing. (Details of drug testing are provided in tables 2.6 and 2.7, p.36)