It seems that the Fallout 76 Beta will be launching on Xbox One first, before coming to PlayStation 4 and PC later down the line. This is according to a recent update to Fallout 76's official FAQ section.
With regards to what platforms the beta would be coming to, the FAQ gives the following details:
The B.E.T.A. will be available on Xbox One, PlayStation 4, and on PC (via Bethesda.net). Stay tuned for exact timing for each platform here and @Fallout on Facebook, Twitter, and Instagram. Please note that the B.E.T.A. for Xbox One will begin first, followed by other platforms.
It makes sense that the Fallout 76 beta would feature a period of timed-exclusivity on Xbox One, given Bethesda’s close relationship with Microsoft in the past. Most recently, a new trailer was premiered at Microsoft’s Xbox E3 2018 Press Conference, before being later shown during Bethesda’s E3 2018 event. During Microsoft's E3 2018 conference, it was also announced that Fallout 4 was being added to Xbox Game Pass.
Details are still pretty thin with regards to the Fallout 76 Beta. We still have no idea when it will go live, what it will feature or just how long it will be exclusive to Xbox One. What we do know is that the only way to gain access is to pre-order the game, with buyers receiving a code that they can redeem when the beta goes live.
At E3 2018, Fallout 76 was confirmed to be an online-focused experience. Players will enter servers along with dozens of others and can complete quests, build camps or attack each other. Fallout 76 will release November 14, 2018 on Xbox One, PS4 and PC.
For everything we know about the Fallout 76 Beta so far, head over to our Fallout 76 Beta Guide. We’ve also been putting together all the info on the new features in the game in our Fallout 76 Guides hub. You’ll find info on settlements and camps, new creatures and more.