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.

Trump tells Ukraine's Zelenskiy to stop hitting Russian diesel
Rescuers search for 130 people after Indonesia passenger ship sinks; six dead
Russia hits passenger train on Ukraine's border with Poland, just misses 'diplomatic train'
Russian drone attack injures five in Ukraine's Odesa, officials say
Philippine ferry fire victims may take months to identify, authorities say
