From [wiki=e20d37a5d7fcc4c35be6fc18a8e71bfa]Paris[/wiki], by A13 (toll).
From [wiki=30e76a2f135197ac4a7eb529ec2b787f]Cherbourg[/wiki] by N13.
From [wiki=25f815808553ecb1af140011841c1a22]Rouen[/wiki], by A13 or N175 (toll).
From [wiki=5f12cfc16406d156d3c4ed54f00556f9]Rennes[/wiki], by A84.
From [wiki=9b6b4233a624fd66f3218841d617f3b1]Tours[/wiki] and [wiki=a2cc484ce8fefe3d1f92c042e3b92fe3]Le Mans[/wiki], by N138, via N158, at Sées.
Trains leave about every 2 h from [wiki=e20d37a5d7fcc4c35be6fc18a8e71bfa]Paris[/wiki] Saint-Lazare station to Caen and Cherbourg. It lasts about 2 h long and costs 33.30 €. If you book early, you can get tickets as cheap as 15 €. Out of rush hours, tickets cost 22.40 € for people under 25.
Note that the train posting in Paris St-Lazare can be confusing to the first time traveler. The train line number ("la voie") is not posted unil 15-20 min before the departure, so do not panic if you arrive earlier than that (notice that the train will be at a line number near the office "Grandes Lignes"). Look for the train heading to Cherbourg. Caen will not be the listed destination, as it is a stop along the way. Do not forget to punch ("composter") your ticket in one of the yellow machines before boarding to validate your ticket.
Trains to the West Coast, including [wiki=7eaea965722999bd19955231f358c15a]Les Sables d'Olonne[/wiki], [wiki=3c771d41f526725acc20def993467e2d]La Rochelle[/wiki] and [wiki=a6f0077b898dc8d408c08168a2c44259]Bordeaux[/wiki] can be reached from Caen via interchanges at [wiki=a2cc484ce8fefe3d1f92c042e3b92fe3]Le Mans[/wiki] and [wiki=62ba359fa6b58bea641314e7a4635cf6]Nantes[/wiki].
Ferries cross the Channel from [wiki=da871503f6796db5142177b404db4fbe]Portsmouth[/wiki] (UK) to [wiki=4389b9f2ee098c0cdb86024af6f30d98]Ouistreham[/wiki], 15 km north of Caen.