Meta in January said it would lift Trump's suspension "in the coming weeks" and would institute heightened penalties of a suspension between one month and two years if the former president violated its content policies again.
He had 23 million followers on Instagram and 34 million on Facebook as of January.
Trump now regains access to key platforms for voter outreach and political fundraising ahead of another run for the White House in 2024.
The Meta move follows Elon Musk's decision to unblock the former president from Twitter.
During his suspension from social media platforms, Trump created his own, called "Truth Social," which has never gained the "numbers" he generated on the others.