Seven and a half months after Halo Infinite's launch, campaign co-op is nearly ready for prime time. It just has a few kinks to work out first, and that means a beta test: beginning Monday, July 11, anyone who owns the Halo Infinite campaign or subscribes to Xbox Game Pass will be able to try out online co-op.
The entire campaign will be available in the co-op beta, though there are a few hoops to jump through first. All PC players who want to participate will need to register to be a Halo Insider, and you'll have to download a separate build of the game and start a fresh save file to get online. Progress will not transfer over to or from an existing save. And you'd better sign up pronto: 343 Industries says if you aren't a registered Halo Insider by July 5, you may not be able to access the network co-op test via Steam. 343 also notes July 11 is the targeted start date, but it is possible it could be delayed if any unexpected issues pop up between now and then.
Console and Game Pass players will additionally need to sign up for the Xbox Insider program, which Microsoft has a guide to on its support site.
In an interview on the Halo Waypoint site, 343's designers touched on some of their goals for Infinite's co-op, confirming that progress you make in a co-op session will count towards playing singleplayer—it won't be a separate save (once the mode launches out of beta, that is). In a nice change from previous Halo games, progress will count for all players, too, and not just the host. The ability to replay missions, absent at launch, will also be in testing during this beta.
The devs also answered my biggest question about how Infinite would handle co-op: exactly how free we'll be to explore the open world together. The answer is: somewhat free. You'll have to stick within 1,000 feet of each other, or risk being killed and respawned beside your nearest teammate. 343 claims it's a big enough radius to tackle objectives like Banished bases together, from opposite sides, without issue—but you definitely won't be free to roam the map independently. Keep that in mind if your co-op partner is prone to flights of fancy, and maybe don't let them get into a Banshee.
The beta is expected to run through July 22, and supports up to four players.