Individuals from Unite working for Arriva at Croydon, Thornton Heath and Norwood stops began strike activity at 03:00 pm.
Drivers, whose courses remember those for Streatham and Brixton, dismissed a subsequent compensation bargain after a beneath expansion pay proposition of 1.5%, the association says.
A representative said the compensation offer that was advanced "completely met Unite's expressed goals".
Transport for London has distributed a full rundown of impacted courses, including three night transport administrations.
As of 15:00 BST on Monday, there was a decreased help on a further six Arriva courses.
Join general secretary Sharon Graham tweeted that "Arriva's transport drivers are tired of being underestimated".