Roscoff is indeed the "Gateway to Brittany". From the ferry port there are regular bus services to Morlaix (services 52B & 53 - 4 daily in winter) and to Brest (service 40 - 7 daily). Both these services pass through the town centre and from Morlaix or Brest connections to the rest of the region, and Nationally, can be made.
Website below is in French but is reasonably intuitive to navigate even if you don't speak the language.
VERY suprisingly there is no shuttle service to and from the ferry into the Roscoff township.
You may be lucky enough to get a taxi from the ferry into town, BUT there is no taxi rank in the town to get you back.
Plan ahead, do your shopping and sightseeing first and have a late, leisurely lunch. Then have your host order you a taxi back
there is a direct bus service between Quimper and Roscoff . the line number 60 Ticket costs 2 euros . bus leaving Quimper 12.30 arrives actually at the ferry port Roscoff at 15.15 in time for the 16.00 ferry . In the morning there is a bus picking up at the port from the overnight crossing 7.30 ish . bus company reseau Penn- ar-Bed.
this company runs buses all over Finistere . Nearly all tickets are only 2.00 euros
This is something that isn't signposted very well. There is a public footpath which takes you to and from the port following the coast behind the industrial estate.
From the port go past the carpark barrier and veer to the right - pics #1 & #2
Returning to the port: from the Table d'Orientation head directly towards the port from the little car park and you'll see the sign for the "Sentier cotier de Bloscon" - pics #3 and #4
This route is slightly quicker than the main road and much more scenic.
Roscoff's ferry terminal is the Port de Bloscon, situated about 10 minutes walk eastward of the town centre.
The port is served by the Brittany Ferries company which was founded in 1972 as a joint venture between the North Finestre Chamber of Commerce and the region's farming co-operatives. The company was set up with the intention of transporting Brittany produce to the UK and to encourage tourism from Great Britain.
The present day Brittany Ferries company now has its head office in Plymouth but is still owned predominantly by its orginal French shareholders and its fleet of eight ships is amongst the most modern in Europe.
There are two crossings daily to and from Plymouth and a weekly sailing from Cork in Southern Ireland. The ships still cater for both tourism and commercial traffic and are a pleasure to sail. The accommodations are comfortable with ensuite cabins and reclining chairs. There's plenty to do on board including lively bars, good-quality and reasonably priced restaurants, shopping at French prices (especially useful if you want to pick some booze or tobacco) as well as family entertainments and activities.
The average daytime crossing from Plymouth takes about 6 hours (8 hours overnight) and from Cork about 14 hours.
Out of season day trips from Plymouth start from £20 for foot passengers and even during the season there are all sorts of special offers available including hotel packages.
Website has all the details.
Roscoff is connected to the main French railway network via Morlaix to which there are up to 10 coach and train services daily run by the regional TER company with a journey time of about 30 minutes.
Roscoff's railway station is located just off Rue Brizeux, behind the Quaix d'Auxerre, and is well-signposted from around the town. From here you can get through tickets for anywhere else on the SNCF network including TGV services from Morlaix.
Just for my fellow rail travel friends, this little jewel will get you from Roscoff to Morlaix in 30 minutes...travelling in France is just such a pleasure sometimes.