Bethesda has confirmed that all versions of Fallout 4 will be available to download ahead of release.
Whatever console (or PC) you're going to be buying Fallout 4 for, you will be able to download the full game ahead of its release.
Bethesda announced the news today, to many fans' delight.
We can confirm that #Fallout4 will have pre-loading on Xbox One, PS4, and PC so you have a few days to download the game before 11/10
— Bethesda Softworks (@bethesda) October 26, 2015
No exact date was provided, but Bethesda's Pete Hines said to expect it a few days before launch. The game's file size is around 28GB which is lower than most of today's games.
Of course, it being a single-player-only game, you won't run into any server issues on launch, so you should be able to play the second it goes live.