Instagram will finally begin enforcing its policy to allow only users 13 or older to sign up for the service in most countries.
Starting on Wednesday the Facebook-owned photo and video platform will ask for date of birth when someone creates an account on Instagram.
"Asking for this information will help prevent underage people from joining Instagram, help us keep young people safer and enable more age-appropriate experiences overall," Instagram wrote in a blog post announcing the change.
The birthday info will not be visible to other users on Instagram.
But ever since it launched in 2010, it hasn't asked for users to specify their age.
For now, Instagram won't require its existing users - which number about one billion - to verify their ages.
Instagram's date-of-birth requirement for new users comes amid greater regulatory scrutiny over how internet services deal with data from kids.
Specifically, the US's Children's Online Privacy Protection Act (COPPA) prohibits services from collecting personal info from kids under 13.
In September, YouTube entered into a $170 million settlement with the US Federal Trade Commission and the New York Attorney General for alleged COPPA violations.
That has led YouTube to adopt new policies, including requiring all creators to designate whether their videos are made for kids.
Many YouTube creators are concerned the new rules will hurt their monetisation or could expose them to fines if their content is mislabeled.
Earlier this year TikTok, the popular short-form video app owned by China's ByteDance, paid $US5.7 million to settle similar FTC allegations that it illegally collected personal info from children. TikTok now requires all users to enter their birthdays.
Instagram said that in the next few months, it will use age information "to create more tailored experiences, such as education around account controls and recommended privacy settings for young people".
Facebook already requires users to enter their birth date when they sign up. If Instagram users have linked their Facebook accounts, Instagram will add the date of birth on the Facebook profile.
In another change intended to boost safety, Instagram is adding the ability for users to control who can send them direct messages.
Users will have the option to allow only people they follow to send them DMs or add them to group threads.
"People who enable this setting will no longer receive messages, group message requests or story replies from anyone they have not chosen to follow," Instagram said.