Over 20,000 of Network Rail's staff will be working on the company's Railway Upgrade Plan this Christmas, including making improvements via the Thameslink Programme at London Bridge.
Improvements to the station are going to affect journeys over the festive period between Christmas Eve and 3rd January 2016.
However, passengers in London are still going to be able to reach the city via diverted services and there will be replacement bus services offered in lieu of available trains.
Thameslink Programme director Simon Blanchflower has said that the service provider is grateful for the patience of its customers, but "with fewer passengers travelling [over Christmas] than at other times, this gives us the best opportunity to do this major work".
Southeastern's managing director David Statham added that the aim of this work is to "improve rail infrastructure and passengers' journeys".
After the work has taken place, passengers can expect more trains to more destinations that will be more reliable.