The account @sussexroyal was launched on Tuesday April 2 in the UK and attracted more than 300,000 followers in a matter of seconds.
"Welcome to our official Instagram; we look forward to sharing the work that drives us, the causes we support, important announcements, and the opportunity to shine a light on key issues," the couple's first official post read.
"We thank you for your support, and welcome you to @sussexroyal."
Harry and Meghan previously shared the @Kensingtonroyal account with the Duke and Duchess of Cambridge.
Since parting ways, Prince William and Kate have replaced the original profile picture of the 'fabulous four' to one of them with their three children - George, Charlotte and Louis.
The separate social media accounts come as Meghan and Harry prepare to move into Frogmore cottage and hire their own PR and communications team.