The quickest route from London to Cambridge is by train. Trains go from London Kings and London Liverpool Street.
Trains from London Kings Cross to Cambridge Station usually take 45minutes. The Fast Trains run every 30mins at quarter past and quarter to the hour.
Trains from London Liverpool Street to Cambridge station usually take 1hour28mins and usually run every 30mins.
Peak times can be really busy (and expensive) so try to aim for off-peak times (9:30am-5:30pm). Make sure you plan ahead and check the train timetable for further details.


 
Fast Trains run every 30mins. Last Train is at 00:32.
 

 

 
The other alternative is to catch a National Express coach from London Victoria to Cambridge. Much cheaper and drops you off right in the centre of town but its also much slower! Buses run every 30mins from London Victoria Coach Station. The last coach of the day departs at 11.30pm.
London Victoria Coach Station is a short walk away from the tube, and you can get to victoria on the Victoria Line, the District Line and the Circle Line.


 
Every 30mins from Victoria Coach Station. Last Coach at 11:30pm