The cat was let out of the bag early on this, but today Microsoft made it official during its Xbox 20th Anniversary event. Halo Infinite’s free multiplayer mode is available now.

Gamers can access the free standalone mode now on Xbox One, Xbox Series X/S, and PC. It will become available on Xbox Cloud Gaming later today at some point.

In honor of Halo's 20th anniversary, your Spartan journey officially begins today. Dive into Season 1 of #HaloInfinite, in the multiplayer beta starting today on Xbox and PC!

🎁 https://t.co/WUyHTqp6yp
📄 https://t.co/uCxf7tYDV4 pic.twitter.com/k28WPYTqAO

— Halo (@Halo) November 15, 2021

The full campaign is scheduled to launch on December 8 at which point all your multiplayer progress will carry over.

[Source: Microsoft]