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.
According to BBC, 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."
Members of the Rail, Maritime and Transport union (RMT) voted overwhelmingly for strike action after nine months of negotiations failed to resolve a long-running dispute over pay and conditions.
Transport for London (TfL) has offered a 3.4% pay rise which it described as "fair" but said it cannot afford to meet the RMT's demand for a cut in the 35-hour working week.
Further talks have also failed to end in an agreement, but Nick Dent, London Underground's director of customer operations, said it was not too late to call off the strikes before causing chaos in the capital.