[1] Barnham is the junction station for the short branch to Bognor Regis.

It has eastbound services to London Victoria via Horsham and Gatwick Airport, Brighton via Worthing and Littlehampton via Ford, as well as westbound services to Bognor Regis, Portsmouth, Southampton.

Trains travelling from east to west (i.e. heading towards Chichester and Bognor Regis) sometimes divide (or attach in the case of west to east services) at Barnham, particularly services on Sundays.

The typical off-peak service in trains per hour is:[2] In the peak hours, the station is served by a single service between Bognor Regis and London Bridge via Littlehampton.

Until May 2022, Great Western Railway operated limited services between Brighton, Portsmouth Harbour and Bristol Temple Meads that called at Barnham.