The changes are due to engineering work or seasonal changes.
These will affect trains from Saturday to Bank Holiday Monday (August 23 to August 25).
We have outlined and simplified the details so you can plan your journey this weekend.
On the bank holiday, all Southern services will run to an amended timetable.
Saturday (August 23):
Engineering work is taking place between Redhill and Tonbridge, closing all lines throughout the whole weekend.
Between these times, buses will replace trains between Redhill and Tonbridge.
Please note that the bus stops in Edenbridge are located at either Main Road or Swan Lane.
The bus stop at the Swan Pub will be for buses towards Redhill, and the opposite side of the road will be for buses towards Tonbridge.
Sunday (August 24):
Until approximately 8.30am on Sunday morning, trains between London Bridge and Caterham will be diverted, calling additionally at Selhurst, running to an amended timetable with extended journey times.
Trains will not call at Norwood Junction.
Paper tickets will be accepted at no extra cost on London Bus route 157 between West Croydon and Crystal Palace (via Norwood Junction).
Engineering work is also taking place before 8.30am and again after 10.30pm between Polgate and Hastings or Ore, closing some lines.
Until approximately 8.30am on Sunday morning and from approximately 10.30pm until the end of service on Sunday evening, buses will replace trains between Polegate and Eastbourne, Hastings, and Ore.
Journey times will be increased when using replacement buses.
