Liverpool may not be the first place that comes to mind for winter water swimming, but there are several swim locations around the city docks. On a recent visit I booked a Sunday morning swim for £5 via Liverpool Water Sports only then to mistakenly walk past the correct dock and encounter an entire different group of swimmers getting ready to enter the water. They were incredibly kind and welcoming and let me swim with them even though they were from a different association. The water temperature that day was 12 ° and the visibility was surprisingly good. The water was aerated by several pumps and it was a nice saline/fresh mixture. One of the swimmers was a dedicated ‘polar bear’ and her partner described all the swim locations they have visited over the past years seeking out cold water. As I was getting out, we witnessed a flock of geese zoom overhead with a wayward one flying straight into the bridge. Lucky, the goose made a full recovery. Here’s a link to Liverpool Water Sports but other groups of swimmers are available. Highly recommended.
https://www.liverpoolwatersports.org.uk/activities/open-water-swimming