Some route indicator posters had to be pulled from station walls last month after the two new stations were shown the wrong way round, with Nine Elms rather than Battersea Power Station at the end of the line.
Transport for London on Thursday said that the final cost of the extension, which will link to the Northern line at Kennington, had come in £160m under budget, bringing the estimated final cost to £1.1bn.
The first train is scheduled to depart from Battersea Power Station at 5.28am on Monday. There will be an initial peak time service of six trains per hour on the extension, increasing to 12 trains per hour by mid-2022.
The extension will bring the power station – which is due to open next summer as a massive shopping, entertainment and office block, with in-built apartments for the super-rich – and the wider Nine Elms area within 15 minutes of the City and West End.
Both new stations are in Zone 1 and Kennington has become a Zone1/2 station, to avoid penalising passengers using it as an interchange.
Major construction on the 3km twin-tunnel extension began in 2015. Both will be step-free from street to train, bringing the total number of step-free stations on the Underground to 88.
Carl Painter, London Underground area manager responsible for the two new stations, said: “There is a palpable air of excitement behind the doors in both of our state-of-the-art new stations as around 100 staff get ready to welcome customers from Monday.
“London Underground stations have a long history of helping to define a neighbourhood’s identity, in gluing communities together and providing a highly visible landmark that helps visitors to navigate.”