Can I solo?

[Niwashi]

You'll have to group nine times for dungeons and I think it's three times for primal fights to get through the story. And reaching max rank in your Grand Company will require two more dungeons. (EDIT: make that 4 more dungeons for your Grand Company. I was thinking of the two you get GC quests to do, but forgot there are another two you'll need to do in order to get all the mobs for your GC hunting log.)

The rest of the story (i.e. the vast majority of it) can be soloed. There are also some sidequests for solo play, and levequests. There are FATEs and a hunting log to give some direction and meaning to grinding mobs. Once you get into your 40's, there are several beast tribe factions to gain rep with through repeatable solo quests. And once you get near or at max level, there are open world hunts you can take part in to earn endgame gear. Plus there's a crafting system if you like that part of solo play as well. So there is always something to do that can be done solo.

So you can treat the game as mostly solo if you choose, provided you're willing to group occasionally for those 12 or 16 required runs. Most players choose to repeat dungeons a lot more than just the initial required run through them, though. Repeating them is the best source of XP in the game (not really needed if you're focusing on a single class/job which will level well enough through the story quests, but if you want to level up several or all classes, you'll run out of quests and need additional XP sources). They're also where a lot of the best gear drops, so people farm them for gear.


EDIT:
Incidentally, my previous favorite MMO before this one was LOTRO. It's an almost entirely solo-able game, and I rarely group there. When I first got to the initial set of required dungeons in this game and found we'd have to group up periodically to continue the story line, I was worried about that, but I've found I actually really like it. While it's possible to meet mean or annoying players in a dungeon, it's actually quite rare. The vast majority of people I've played with have been either friendly and helpful or else silent and just focused on completing the content. I've had a lot of fun working out how to fulfill my role in a group while simultaneously supporting and relying on other players in their respective roles. It adds an extra element to the class/job system that you don't get to see during solo play.