The Polar Bear Challenges run from 1 November to 31 March and the aim is to complete a set number of swims and distances outdoors in the sea, river, lake or unheated lido during this period over the winter
The Polar Bear Challenge is run under the clothing rules of the International Ice Swimming Association and the Channel Swimming & Piloting Federation which means that the only attire allowed is one standard swimsuit ( which may not extend over the shoulders or below the knees ), a single standard silicone or latex swimhat ( no bubble or fancy hats), goggles, noseclips and earplugs if required.
The Penguin challenge does not have any clothing rules so you can wear anything you like including wetsuit. gloves, boots etc.
Swimmers from all countries are welcome to take part but your winter swimming temperatures must be no higher than UK winter swimming temperatures.
More info here https://polarbearchallenges.com/