From North Greenwich station, the walk is literally 200 meters. Easy. But some lunatics walk from Greenwich town centre through the foot tunnel under the Thames. It’s a dark, tiled, echoey tunnel built in 1902. It smells like damp ambition.
Walk it if you want to feel like a Victorian ghost. It takes 15 minutes and you’ll exit right at the arena. Bring a torch, unless you enjoy tripping over a unicyclist. (Yes, there’s often a unicyclist.)
O2 Arena London Map , The O2 London – HEFS