Sailing from Roscoff to Plymouth overnight means that you arrive at 6am the next day. The Duc de Normandie and the Val de Loire are the ships operating this route.
Roscoff is a quiet fishing village set within the beautiful area of West Brittany. You can go to all parts of Brittany by taking toll free motorways, which makes it an ideal gateway to the Brittany region, the rest of France and the whole of Europe .
Roscoff as a port that was opened in 1973 in an attempt to help the Breton economy. Ships go to both Plymouth and Cork in Ireland , which allows tourists to go there but also encourages trade to happen between the more traditional celtic nations of Ireland, Southwest England and Brittany. A little known fact is that when Mary Queen of Scots came to France in 1548 to marry Francois, son and heir of Henri II, she landed in Roscoff. The young pretender, Bonnie Prince Charlie, landed at Roscoff in 1746 having been defeated at Culloden.
Almost all of the activity in Roscoff is confined to the old port and the rue Gambetta. The other roads are not much more than residential back streets where people come to retire in home and institutions. The centre of Roscoff is quite a way from the port and the SNCF station, which helps to maintain the character of the old town.
At the far end of Rue Gambetta is Notre-Dame-de-Croas-Batz, which is a sixteenth-century church featuring an ornate Renaissance belfry with a protruding stone cannon and sculpted ships. Should you stand at the side you can see rows of bells hanging one above the other in galleries as if on a wedding cake. Beyond the church is the grand Thalassotherapy Institute at Rock Roum. The best beach in Roscoff is the Laber which is about a kilometre away surrounded by expensive apartments and hotels
The old harbour mixes fishing with some low-key pleasure trips over to the Ile de Batz. This island seems to be almost walkable. There is a narrow pier that stretches over 300 or 400m towards it but that suddenly drops off into rocky waters. When the tide is in you can find good vantage points at the Pointe de Bloscon and at the fisherman's white chapel, called the Chappelle Ste-Barbe. Note that the tide does go out a long way. Where the tide is dictates where you embark the boat trips.
An amusing story is that Henri Olliveir took onions from Roscoff to England in 1828, which launched a classic French image (think about it).