All US visa applicants will now have to undergo social media screening.
The US State Department regulations said applicants will have to submit social media names and five years' worth of email addresses and phone numbers.
"National security is our top priority when adjudicating visa applications, and every prospective traveller and immigrant to the United States undergoes extensive security screening," it said in a statement.
"We are constantly working to find mechanisms to improve our screening processes to protect US citizens while supporting legitimate travel to the United States."
Certain diplomatic and official visa applicants will be excluded from the screening.
First proposed in March 2018, it's expected to affect about 15 million visitors.
Previously, it was applicable only to those applicants who needed additional vetting.