Hi there

The Brittany TER website says all trains accept bikes on a limited basis (presumably first-come, first-serve).

http://www.ter-sncf.com/Regions/bretagne/Fr/TER_Pratique/Default.aspx
"Transport de vélos dans les cars et TER Bretagne
Tous les TER Bretagne acceptent les vélos dans la limite des places disponibles."

I've emailed a fellow cyclist in Brittany, as well as the tourist board to double check - will let you know if I hear any different.

Hi again JF,

I've just heard back from the tourist board and they say there are 3 to 6 dedicated spaces on each train on the Redon-Lorient line, but no possibility of booking. They advise travelling between 10am and 6pm (ie outside of rush hour) to guarantee a space.

Hope you have a good trip.
Cheers.

That's great. Thanks for your help.

Your question has already been answered, but thought I'd just add a bit more. All TERs in France accept bikes, as far as I know. If you're lucky you'll get one of the newer ones with nice hooks and lots of space right by the entrance, however even in the older TERs you have a car (usually at one or other end) with space. When in doubt, just chuck it on.