Baines will work across Première, JCDecaux's premium portfolio. She joins from CBS Outdoor, where she was national sales account manager.
Baines joins at a key time, in the run-up to the London Olympic Games in 2012, with JCDecaux investing in its premium portfolio to reach Londoners on the move.
St Paul joins group head Ged Glover's team at JCDecaux and will work across the Starcom MediaVest and Kinetic groups.
St Paul prev-iously worked at Titan Outdoor, where she was account manager on the national sales team for Mindshare and Starcom MediaVest.
Rai, a former senior account manager at student media company Sub.TV, will work on JCDecaux's StreetTalk phonebox advertising.