London Underground staff have started a five-day walkout over pay and conditions.
Members of the Rail, Maritime and Transport (RMT) union are carrying out rolling action over pay and fatigue management, and have asked for a 32-hour week.
There will be limited service until 18:00 BST on Sunday and little or no service between Monday and Thursday. The Elizabeth line and the Overground will operate as normal but are expected to be much busier, along with buses and roads.
Transport for London has offered a 3.4% pay rise and said it "welcomes further engagement with our unions", but said a reduction in the contractual 35-hour week "is neither practical nor affordable".
A separate dispute on the Docklands Light Railway will stop services on Tuesday and Thursday.