Facebook will integrate WhatsApp, Instagram and Messenger.
The technology giant said the move is intended to create “the best messaging experiences” for its billions of users around the world.
Each app will remain distinct from each other, though the underlying messaging infrastructure will be unified, according to people familiar with the matter.
A spokesperson for Facebook said the merger would deliver a messaging platform that is “fast, simple, reliable and private”.
The spokesperson added: “We’re working on making more of our messaging products end-to-end encrypted and considering ways to make it easier to reach friends and family across networks.”
No official details have been released but the merger is expected to take place by early next year, The New York Times reported, who cited people familiar with the matter.
The messaging merger is a backtrack on Facebook CEO Mark Zuckerberg’s original stance that both Instagram and WhatsApp would operate autonomously from the social network.
Facebook acquired photo-sharing platform Instagram for approximately $1 billion (£761 million) in 2012, before taking over the messaging app WhatsApp in 2014 for an estimated $19.3 billion (£14.7bn).
Both apps have since experienced rapid growth, though all original founders of the apps have since left Facebook.
WhatsApp employees were reportedly upset by plans to merge the app’s messaging services with the other apps, making their views known during a contentious staff meeting in December.
Facebook said in a statement: “As you would expect, there is a lot of discussion and debate as we begin the long process of figuring out all the details of how this [merger] will work.”