9-13 hours; even though that doesn't sound like much, the Pikmin series isn't built on how long the game is.
Pikmin 3 is an awesome game. It's longer than the first, it's just a bit shorter than the second, but they really did an awesome job on it. I felt that there was a lot of replay value in it, so much as to make me play it for a second time right after playing it. (Usually it takes a month for that to happen with some games)
Also, I use nunchunk and wii mote with gamepad as map, but one night I got so excited that I managed to save Pikmin at the last second, I shook my hands in excitement, and all the Pikmin that captain had were all dismissed, and I lost 40 some Pikmin because of it. It's sad, but I just wanted to share that.
Also, with that circle around the onion, it makes playing the game SO much more easier, especially when you are pushing through to the last seconds. Like, the first playthrough I was very cautious and when it said hurry up, I would send my captains to get any loose Pikmin and return to base to wait, but in my second run-through, I found myself be a lot less cautious and using my Pikmin till the last second, which cost me more Pikmin than the first time (the first time I didn't lose any Pikmin at night except for one night and it was three).
I hope that Pikmin 4 or some DLC is already in production, because I'm positive that the success of Pikmin 3 was just too great to just leave it there.