The most probable source of the name is the shape of the island - it resembles a wedding cake, particularly when the white water breaks over the island, giving the appearance of 'icing'. Another theory is that bird droppings on the island gave the appearance of icing on a cake.
The island is a good scuba diving spot and also is the site of ANZAC day commemorations by the local surf community. Every year in commemoration of ANZAC day, surfers load up their surfboards and backpacks with cartons of beer and drink, and paddle out on their boards from Coogee Beach to Wedding Cake Island.
In 1975, "Wedding Cake Island" was the title of a popular surf music instrumental single by Australian rock music band Midnight Oil, with lead singer Peter Garrett and guitarist Martin Rotsey being local residents off Coogee Beach. The track was re-released in 1980 on the EP Bird Noises. It was also covered by the Australian surf group The Atlantics on the album Delightful Rain in 2006. The Atlantics often include it as part of their live set, with Midnight Oil's blessing. Now, Australian instrumental surf rock band, The Break (which includes Midnight Oil members: drummer Rob Hirst and guitarists Jim Moginie and Martin Rotsey, Violent Femmes bassist Brian Ritchie and Hunters and Collectors trumpet player, Jack Howard) play the song regularly in their shows, being an inaugural part of Midnight Oil's history of wanting to do instrumental surf rock music.