Police will be carrying out patrols on trains to Portsmouth ahead of the south coast derby.
The Blues are set to host Southampton at Fratton Park on Tuesday in the Carabao Cup.
It is the first meeting of the arch-rivals at Pompey’s ground since December 2011 and the first time they have played each other since a 2-2 draw in April 2012.
Hampshire Constabulary will not be running a ‘bubble’ operation, so Southampton fans will be able to make their own way to the city for the game at Fratton Park.
South Western Railway will be putting on extra train services on Tuesday between Southampton and Portsmouth.
On Southampton’s website, the club says that there will be three extra trains – the first will be leaving Brockenhurst at 5.55pm, calling at Southampton Central and Fratton only.
This train will consist of eight carriages. It will stop at Southampton Central at 6.10pm.
There will be a return train leaving Fratton at 10.34pm, heading to Southampton Central only. This train will consist of eight carriages.
There will also be a train leaving Fratton at 10.14pm. This will stop at Hilsea, Cosham and Portchester and Fareham.
Southampton have also warned fans that British Transport Police (BTP) will be carrying out patrols on the trains to Portsmouth.
In a statement on the club’s website, they wrote: ‘British Transport Police will be carrying out patrols on these trains and others throughout September 24th, with support of officers from Hampshire Constabulary.
‘These officers will be there to help ensure the safety of everyone on board and if you have any concerns during the journey please speak to them.’
Official coach travel costs £16 return, and departs from St Mary’s at 5.15pm.