It includes trains starting earlier and ending later on some routes and extra carriages being added to services.
Southeastern also has 1,000 additional temporary staff to assist passengers over the summer.
Alison Nolan, from the firm, said: “From this weekend, our services will be extremely busy.
“Queues are to be expected at many London terminal stations.
“We recommend passengers travelling during Games-time check to see how their journey is likely to be affected.”
The rail firm added that only essential maintenance on its network would be carried out during the Games.