London is a city that rewards walking. Not the frantic tourist kind — head down, ticking boxes — but the kind where you give yourself a full day, start at one end of the Thames and let the river do the navigation. This route does that. It takes about eight hours at an unhurried pace, covers the landmarks you came to see, and earns its lunch stop.
Start at Tower Hill tube station (District and Circle lines) and walk to Tower Bridge. You'll see it as you come up from the underground and it doesn't get less impressive on closer inspection. The Bridge Exhibition lets you walk across the glass floor walkway with the Thames visible below, and goes through the Victorian engine rooms. Tickets are around £12 for adults, best booked online in advance. Allow 90 minutes.
From Tower Bridge, cross to the south side of the river and walk west along the Thames Path. This is the best part of the day. The path runs continuously from here all the way to Westminster and you're walking with the river on your right and the City of London skyline on your left. You'll pass Hay's Galleria, the Golden Hinde, the Shard on the south side, Shakespeare's Globe (the exterior is free, guided tours run through the day).
Borough Market is about 20 minutes along the path from Tower Bridge, just past London Bridge. Stop here for lunch. It's open Tuesday to Saturday, 10am to 5pm. This is genuinely one of the better food markets in Europe — the kind where you make several rounds before committing. Budget about £15–20 for a proper lunch. It's busiest between 12 and 2pm; arriving at 11:30 gets you ahead of the crowd.
After Borough Market, continue west. Tate Modern is another ten minutes on foot, in the old Bankside Power Station. Entry is free for the permanent collection. The Turbine Hall alone is worth five minutes of your time regardless of what's in it — the scale of the building is disorienting in a good way.
From Tate Modern it's another 30 minutes west to Westminster Bridge, passing the South Bank arts complex, the BFI, the London Eye (tickets around £35 if you want to ride; the exterior is free and the views from the bridge are honest compensation if you don't). Cross Westminster Bridge for the view of the Houses of Parliament and Big Ben reflected in the Thames — this is the shot. Stand on the bridge rather than the embankment.
If timing works, walk from Westminster Bridge to Buckingham Palace via St James's Park — about 20 minutes. The Changing of the Guard happens at 11am on Mondays, Wednesdays, and Fridays in summer, and lasts 45 minutes. The full schedule varies and is confirmed about six weeks ahead on the Household Division website. If it's not a ceremony day, St James's Park in July is worth the walk regardless.
