Ioan Gruffudd performed his own base jump stunt, which he described as his favorite part of the shoot.
Ioan Gruffudd was the only member of the cast to be a fully qualified diver before the film began shooting.
In an unfortunate coincidence, Agnes Milowka, one of the film's diving doubles, drowned after running out of air shortly after the film was released.
At one point Richard Roxburgh asked the art department if they could lighten the load of the pack that he has to carry for most of the film. The next morning they presented him with the reduced weight pack, telling him that they'd managed to take 2 kgs off the total weight. Of course, they hadn't bothered doing anything at all but Roxburgh was convinced that they had.
All the underwater sequences were shot in a large water tank at the Village Roadshow Studios in Queensland, Australia.