Kids unter 5 Jahren reisen in London immer kostenlos, wenn sie von einem zahlenden Erwachsenen begleitet werden.
If a child is:
With someone who has a valid ticket, is using Oyster to pay as they go, has a Freedom Pass or has a Veterans Oyster photocard
The child gets:
Free travel on buses, Tube, trams, DLR, London Overground and National Rail