A strike by conductor-members of the RMT Union will hit Uckfield Line trains again today and tomorrow.
Trains expected to run this morning are at 8:04 and 8:34. Those coming back from London Bridge are shown as leaving London Bridge at 16:08 and 16:38.
Southern Rail says passengers are strongly advised to check train times again before they travel.
The company says where necessary it will run replacement buses to keep commuters moving.
Further strikes have been threatened from Thursday, December 22, to Saturday, December 24, and from Saturday, December 31, to Monday, January 2.