James Buckley took ill during the filming of the outback scenes in Marree thinking he was having a heart attack, but it turned out to be indigestion from eating chips and lager too fast.
The nightclub in Australia where Will, Simon and Neil first see Jay is actually the Ministry of Sound club in Elephant & Castle, London.
The song Will plays on the guitar around the camp fire was originally due to be "You're Beautiful" by James Blunt, but Blunt wouldn't allow the song to be used in the film. Simon Bird, who doesn't play the guitar, spent 3 months learning to play "You're Beautiful" before it was changed.
In the opening scenes, you can clearly see that Neil's email address is "sexydanceneil95@gmail.com"
This is most likely the last appearance of the Inbetweeners, as Bird, Buckley, Harrison and Thomas are all too old to continue playing these roles, and the original film was meant to close the series; but a sequel was only made due to popular demand.