Prime Video made it rather clear that the wait between seasons of Fallout would be shorter following the gap between the first and second seasons, and clearly we're now seeing this made reality.
The Film & Television Alliance has published an article wherein it states that the third season of Fallout will begin filming in Santa Clarita, California as soon as May 1, 2026. Considering that the second season won't even wrap up until early February, we could very much be staring down a world where the third batch of episodes debut in 2027, leading to a much more consistent launch schedule.
The report goes on to add that Season 3 is currently well into pre-production and that Graham Wagner and Geneva Robertson-Dworet are back as the showrunners once more. Beyond this, it notes that the shoot will progress into early summer and that visual effects teams should expect "to be a major component" again in the post-production phase.
As for where Season 3 will take the show, we'll know more for a fact in a few weeks when Season 2 has concluded and left the door open to the next phase of the journey, but there are claims it could have ties to Fallout 5...