The trick is to find enough time to spend in the water.
Photo: London Fields Lido, Hackney, London. Remarkably the only 50 metre outdoor heated pool in London
Pool work over the winter is fine – aiming for 20km to 30km per week through October to April.
Once “summer” starts in the UK, it is time to move that to Dover. It is possible to train in the ocean once the water gets to around 10°C (50°F). It is possible to get in and train – just not for very long.
The heart of channel preparation is the 6-hour swim. A mandatory step for a swimmer to be allowed to attempt to swim the channel is to complete a qualification 6-hour swim in water under 15°C (59°F). A good training weekend in Dover involves a 7-hour swim on Saturday, followed by a 6 hour swim on Sunday.