Jackman first portrayed the aggressive Canadian mutant in X-Men back in 2000. Since then, he's reprised the role in X2: X-Men United (2003), X-Men: The Last Stand (2006), X-Men Origins: Wolverine (2009), X-Men : First Class (2011) -- although just in a very brief cameo -- The Wolverine (2013) and X-Men: Days of Future Past (2014).
Jackman is set to return as Wolverine for X-Men: Apocalypse, which comes out in 2016. His co-star Jennifer Lawrence also recently confirmed that Apocalypse will be the last film in which she'll star as the shape shifting mutant Mystique.
It's been rumored that one more solo Wolverine project was being developed by Fox, so it's unclear if Jackman's "one last time" comment is referring to that untitled rumored project, or Apocalypse.
Either way, it kind of seems like Jackman is pretty addicted to playing the legendary fan favorite mutant, and this "one last time" comment feels like more of an attempt to convince himself that he's leaving the film franchise more than us. This is all totally fine by the fans, because there will always be an audience to watch Jackman knife-punch bad guys.