The measures will effectively mirror those rolled out in Scotland on Friday (15 January), which require arrivals by air, sea and rail to return a negative Covid test result up to 72 hours prior to departure.
England had been due to introduce like measures on Friday, but the rollout was later pushed back to Monday. Northern Ireland is preparing to enact similar rules.
Like England, the Welsh pre-departure testing regime will operate alongside quarantine, rather than replacing it.
Gething said the measures would guard against the import of new strains of coronavirus and provide an additional layer of safety from imported cases.
"We are doing everything we can to slow down the spread of the virus," said Gething. "These new measures will help ensure we prevent new strains of the virus from being imported into Wales.
"We are already asking passengers returning from high-risk countries to self-isolate for 10 days, and these requirements remain in place.
"Added to the requirement to self-isolate, pre-departure tests will provide a further line of defence, helping us control the virus as we continue to roll-out the vaccine at pace."
