There are a number of different routes to consider if you are planning on catching a ferry to France, this is mainly dependant on your location and which is the easisest ferry post to get to in the UK. The main routes that offer ferries to France are:- Dover to Calais, Portsmouth to Caen, Portsmouth to Le Havre or Dover to Dunkerque.

Dover to Calais
P&O
Crossings per day: upto 46 per day
Duration: 1 hr 30 mins

Seafrance
Crossings per day: upto 14 per day
Duration: 1 hr 10 mins to 1 hr 30 mins depending on the vessel.

Dover to Dunkerque
Norfolkline
Crossings per day: Upto 12 per day
Duration: Just under 2 hours

Portsmouth to Caen
Brittany Ferries
Crossings per day: 4 (including 1 high speed seasonal service each day – only operates between March and October)
Duration: 6 hours (day) 7 hours (overnight) 3 hr 45 mins (high speed service)

Portsmouth to Le Havre
LD Lines
Crossings per day: 2 (including 1 high speed seasonal service each day – only operates between March and September)
Duration: 5 hs 30 mins (day – Le Havre to Portsmouth) 8 hours (overnight – Portsmouth – Le Havre) 3 hr 15 mins (high speed service)