The event is said to date back to 1987 when three locals jokingly suggested a January 1 dip as a cure for Hogmanay hangovers. From small beginnings, the event grew in size and popularity during the 1990s, was added to the official Edinburgh Hogmanay publicity material and even broadcast live by the BBC at the millennium.
The event usually attracts around 1,000 people, many in fancy dress, to raise money for charity. And some people come from abroad to take part in the swim.
The official Loony Dook was cancelled for new year 2021 and 2022 because of Covid and the 2023 event was not included in the official Hogmanay programme, but dedicated Dookers went ahead anyway.
Scroll through these pictures to enjoy Loony Dooks past – without having to take the plunge.
1. It's just so cold
These two look as if they hadn't expected the water to be quite so icy when they plunged in to celebrate the start of 2015. Photo: Hemedia
2. Costume party
Around 1,000 New Year swimmers, many in costume, braved the cold water in front of the Forth Bridge on January 1, 2014. Photo: Neil Hanna
3. A New Year wave
Three friends taking part in the 2019 Loony Dook give a wave from the water | Getty Images Photo: Andy Buchanan
4. Balancing act
Loony Dookers brave the chilly waters of the Forth to celebrate the arrival of 2013. Photo: contributed