Passengers arriving from overseas will face a fine or jail if they fail to fill out a Covid-19 passenger locator form.
From today, it's mandatory to provide details of where you will be self-isolating and your contact information.
The passenger locator forms will be used to make sure people who travel here are staying where they said they would.
Anyone who fails to fill one out could be imprisoned for up to six months or face a fine of up to €2,500.
Chief medical officer Tony Holohan says airlines and airports will help ensure forms are filled out.
