Major railway closures are planned for this weekend due to essential engineering works.
All lines serving the route between Brighton and Littlehampton will be shut down on Sunday, April 26.
Train services will not operate through Brighton, Preston Park, Worthing and Littlehampton.
Trains that normally run between Brighton and Portsmouth Harbour or Southampton Central will only serve the section between Littlehampton and those destinations while the work takes place.
A bus network will replace trains on the Brighton, Worthing and Littlehampton corridor. Services from London Victoria to Littlehampton will instead terminate at Brighton.
Passengers should use the National Rail Enquiries Journey Planner to arrange their trips in advance. Replacement transport may experience higher demand than usual.
Travel times will be extended, and those travelling are encouraged to set aside additional time for their journeys.
Some Southern services departing from Portsmouth Harbour and Bognor Regis towards London will have altered departure times, setting off earlier than scheduled on April 25 and 26.
This adjustment is required to accommodate revised Thameslink timetables, which have been affected by engineering works taking place between Herne Hill and Farringdon.
Complete details about substitute services can be obtained from displays at stations or by using the Find a Station section of the National Rail website.
