Yes, there are some places that you can rent paddleboards or go on paddleboard tours in London. I learned to paddleboard with this London watersports company, https://www.active360.co.uk/paddleboarding-london.htm. They offer a range of different options such as private classes, paddleboard lessons, and tours. I was surprised at how much I enjoyed paddleboarding in London as you may feel like London is not really the ideal place for it. Now I go every week and would recommend it to anyone. If you’re just in town for a holiday then you could try one of the tours. A few of my friends have tried them and they said that it was a really unique way to experience London’s waterways.