Season 1 of Underbelly premiered on February 13, 2008.

This series is loosely based on the real events of the 1995–2004 gangland war in Melbourne. It depicts the key players in Melbourne's criminal underworld, including the Carlton Crew and their rival, Carl Williams.

Season 2 of Underbelly premiered on February 9, 2009.

This series is loosely based on real events that stemmed from the marijuana trade centred around the New South Wales town of Griffith. The timeline of the series is the years between 1976 and 1987. A Tale of Two Cities primarily depicts the Mr. Asia drug syndicate and its influence on crime in Australia. Among the characters presented are real-life criminals Robert Trimbole, Terry Clark, George Freeman, Christopher Dale Flannery and the Kane Brothers.

Season 3 of Underbelly premiered on April 11, 2010.

This series is loosely based on real events that stemmed from the nightclub scene of the Sydney suburb of Kings Cross. The timeline of the series is from the years between 1988 and 1999. It primarily depicts the running of Kings Cross and the corruption of police leading up to the 1995 Wood Royal Commission. Among the characters presented are John Ibrahim, Kim Hollingsworth, George Freeman, Lenny McPherson and MP John Hatton.

Season 4 of Underbelly premiered on August 21, 2011.

This series details real events that occurred in Sydney between 1927 and 1936. The series depicts the "razor gangs" who controlled the city's underworld during the era and the violent war between the two "vice queen" powers, Tilly Devine and Kate Leigh.

Season 5 of Underbelly premiered on August 13, 2012.

This series details the real events that occurred in Sydney between 2001 and 2012.

Season 6 of Underbelly premiered on July 28, 2013.

This series is based on the life and career of notorious Melbourne gangster, Squizzy Taylor, and is set between 1915 and 1927.