Southampton City Council update on 19 April said:

Public transport - Coronavirus (Covid-19) update

City Red and Bluestar are now accepting each other’s tickets on common sections of routes to help key workers travel with greater ease during this challenging period. This includes all valid passes and smartcards issued by both operators.

For the latest updates from both bus operators, please visit the City Red and Bluestar websites directly.

Finally, as we [Southampton City Council] have closed the Gateway building until further notice, we are not able to process bus pass applications or renewals in person at this time. If you need to apply for or renew your bus pass, you can still do this by going online here. Alternatively you can email: smartcities@southampton.gov.uk quoting your name, address and date of birth.

Bus tickets and passes