South Western Railway service has said the lines in the Southampton Central area will be closed all weekend due to maintenance work.
CrossCountry, Great Western Railway and Southern services will be affected by this work.
The closures, taking place on Saturday, April 11 and Sunday, April 12, will impact routes serving Bournemouth, Poole, Brockenhurst, Weymouth and Lymington Pier.
Rail replacement buses will operate across the weekend, with non-stop services running between Bournemouth and Southampton Central, alongside additional buses linking Bournemouth with Brockenhurst and other nearby stations.
On Saturday, fast buses will run between Eastleigh, Southampton Airport Parkway and Bournemouth.
On Sunday, services between Bournemouth, Poole and Weymouth will also run to an amended timetable.
However, the afternoon and evening London Waterloo to Poole services will not run.
Passengers travelling to or from stations across Bournemouth, Poole and the surrounding areas are being advised to allow extra time for their journeys and check before travelling.
The works are part of planned maintenance to improve the reliability of the railway network.