Open Water is a 2003 drama psychological horror film loosely based on the true story of an American couple, Tom and Eileen Lonergan, who in 1998 went out with a scuba diving group, Outer Edge Dive Company, on the Great Barrier Reef, and were accidentally left behind because the dive-boat crew failed to take an accurate headcount.
The film was financed by writer/director Chris Kentis and his wife, producer Laura Lau, both avid scuba divers. The film cost $130,000 to make and was bought by Lions Gate Entertainment for $2.5 million after its screening at the Sundance Film Festival. Lions Gate spent a further $8 million on distribution and marketing. The film ultimately grossed $55 million worldwide (including $30 million from the North American box office alone).
Before filming began, the Lonergans' experience was re-created for an episode of ABC's 20/20, and the segment was repeated after the release of Open Water. Clips from the film were also featured on NBC in Troubled Waters, a Dateline episode (July 7, 2008) with Matt Lauer interviewing two professional divers, Richard Neely and Ally Dalton, who were left adrift at the Great Barrier Reef by a dive boat on May 21, 2008.