Parliament Hill Lido

This is a wonderful, bracingly no-frills pool with tremendous atmosphere - the daytime entry charge is worth every penny. Because it's unheated it's blissfully underpopulated most of the time; but beware coming on evenings and weekends when it's really hot -- the queue for entry will stretch round the block. The showers are piping hot. The rough-and-ready changing facilities have attracted some sneers on TripAdvisor, but for the dedicated swimmer they are part of the charm. The cafe is excellent, friendly and not too dear, e.g., a delicious falafel wrap costs £4.50. One drawback, I suppose, is the very shallow, shallow end; a tall lap swimmer will need to watch his or her knuckles!

To update the previous reviewer comments:
There are now lockers for early morning and evening swimmers which either take a lock (your own) or a £1 coin. Unlike many UK pools, which prohibit the use of fins, PH Lido welcomes them. This pool is open year-round and is unheated. The non-summer swim session is limited to the morning. Taking the C11 bus or the Overground, getting off in Gospel Oaks, is the best way to get there. Parking will cost more than your swim. There's a nice cafe for breakfast.

This pool is a good reason to live in North London. It's a great place to train for triathlon or open water swimming, or just for an early morning refresher. It's a huge pool, so it never feels too busy, no matter how crowded it gets. There is only one lane rope but, unless it's heaving, it's not an issue. The water temperature in high summer is about 18º to 22ºC - OK with or without a wetsuit. The best time to go is between 7:30 and 9 AM (they throw you out at 9:30 AM) - it costs only £2.00 and most people are swimming laps. If you go between 7 and 7:30 AM, you have to swim widths (27m). There are no lockers for your stuff in the morning session, so leave valuables at home. The day session is much more expensive (about £5.00) and can get very crowded on hot, sunny day. There are also evening sessions for adults only, mostly lap swimmers, on Mondays, Thursdays, and Fridays, 6:30 to 8 PM.