[1] Officially opened in December 1985 by the Premier of New South Wales, Neville Wran,[2] the park was the largest in the southern hemisphere.

Wonderland Sydney, then known as Australia's Wonderland opened amid much media attention and publicity on 7 December 1985 with financial backing from the New South Wales State Superannuation Board, James Hardie, Leighton Holdings and Taft Broadcasting (through Kings Entertainment Company)[3] at Eastern Creek on the junction of Wallgrove Road and the M4 Motorway.

The developers sought to provide an alternative to the troubled Luna Park Sydney, which had opened and closed multiple times in its recent history.

For many years, Wonderland's flagship ride was 'The Bush Beast' which was the largest wooden roller coaster in Australia.

Unlike the rest of the park, which remained open year-round, The Beach was a seasonal attraction which closed during the winter months (June–September).

CEO Stephen Galbraith stated the September 11 attacks, the 2002 Bali bombings, the collapse of HIH Insurance, the SARS virus, the bird flu virus, consistent losses on the Asian financial crisis, the collapse of Ansett Australia, the Iraq War and the 2003 bushfires all contributed to the park's closure.

[5] Sydney Morning Herald stated that Sunway Group "blames Wonderland's demise on everything except poor management".

[9] The entry way signage at the time of closure, featuring Spider-Man and The Incredible Hulk, was sold to a junkyard in Londonderry in Sydney's north west.

[27] In September 2015 the proposal received financial backing with a $1 billion cash injection from a consortium of investors via the multinational, Fox Petroleum Limited but there has been no further action on the project since then.