The changes are due to engineering work and will affect trains from Monday to Friday (June 9 to June 13).
We have outlined and simplified the details so you can plan your journey this weekend.
Monday to Thursday (June 9 to June 12):
Engineering work is taking place between South Croydon and Oxted, closing all lines overnight from Monday evening until Friday morning.
From 10.45pm until the end of service each night, trains will not run between London Victoria and East Grinstead or between London Bridge and Crowborough or Uckfield.
Passengers can use alternative trains towards Brighton or Worthing to travel from London Victoria to East Croydon, and alternative trains towards Caterham to travel from London Bridge to East Croydon.
Replacement buses will run between East Croydon and Oxted, East Grinstead, Crowborough or Uckfield.
Engineering work is also taking place between New Cross Gate and West Croydon, closing all lines overnight from Monday evening until Friday morning.
The 11.20pm train from London Victoria to London Bridge service will run non-stop between Streatham Hill and London Bridge.
A replacement bus will run from Streatham Hill to London Bridge, calling at all stations via Sydenham.
The 11.58pm train from London Bridge to Streatham Hill service will start at 12.04am (Tuesday to Friday morning) and will run non-stop between London Bridge and Streatham Hill.
A replacement bus will run from London Bridge to Streatham Hill, calling at all stations via Sydenham.
Tuesday to Friday (June 10 to June 13):
The 12.02am, 12.17am, and 12.35am trains from London Bridge to East Croydon service will be diverted between London Bridge and Norwood Junction and will run later than usual.
A replacement bus will run from London Bridge to Norwood Junction via Sydenham.
