The changes are due to engineering work and will affect trains from Tuesday (July 8) to Friday (July 11).
We have outlined and simplified the details so you can plan your journey this week.
Tuesday to Friday (July 8 to July 11):
Engineering work is taking place in the early hours between Haywards Heath and Eastbourne, closing all lines.
At the end of service on these days, the 1.08am trains from Haywards Heath to Eastbourne train will be diverted to run to Brighton.
A replacement bus will run from Haywards Heath to Lewes and from Lewes to Eastbourne.
Journey times will be increased when using replacement buses.
