Colmar to Carcassonne by train

I did the route from Colmar to Carnacssone. I stopped off in Mulhouse for a couple of days to see the auto museum. (There is also a train museum.)

Mulhouse is nothing to write home about. I described it as the Detroit of France.

I also spent a couple of nights in Beaune.

No need to go to Marseille to get to Carcassone.

When are you traveling?

There is an early morning TGV arriving in Nimes about 5 hours later. There are several intermediate stops including Dijon and Lyon. From Nimes to Carcassonne is another 2 hours.

From Carcassonne to St. Malo, consider traveling to Saint Pierre des Corps for the the Loire Valley or La Rochelle on the coast. Possible stops include Toulouse, Bordeaux and Rennes depending on the route you choose.

Rome2Rio is sometimes interesting in its routings.

The 7:16 TGV from Colmar to Montpelier requires no changes. When it reaches its end station at Montpelier you have 15 minutes to change to the Intercity train going only 3 stops to Carcassonne in only 1:23.

It is actually a very easy journey.

Using the source - DB and SNCF. DB who have all the real schedules and SNCF who actually run the trains.

Fair enough, Nigel. The Colmar to Montpelier train stops at Dijon and Lyon, among others. Montpelier is a good option, too.

There are several main train route options from Colmar to Carcassonne, depending on the departure time and day.

The only option with a single change of train is via Lyon (8 hours and 20 minutes total journey time).
With two changes, the first connection is in Mulhouse, and the second can be in Lyon, Nîmes, or Marseille.

There is also a longer option via Paris, which involves changing stations in Paris and taking another train from Paris to Carcassonne via Toulouse.

Train journeys from Carcassonne to Saint-Malo all involve at least two changes of train: the first in either Montpellier or Narbonne, and the second in Paris with a change of station in Paris.

That said, there are many other options besides the most direct train routes. Most of what you're looking for (old town areas, castles, cathedrals, etc.) is often located off the main long-distance rail lines.

jeanm has given you some examples above between Carcassonne and Saint Malo

Unfortunately, a couple of answers are sending you via Vermont and Rome 2 Rio hasn’t worked correctly for years. Marseille is two hours east of Montpellier.

I'm sure Nigel, a former railroad employee, is correct on the early morning TGV direct from Colmar.

I took the direct TGV from Strasbourg to Montpellier yesterday. It's first stop is Mulhouse, so you aren't an early riser for Nigel's 7:16 train, you could take the Colmar to Mulhouse train and change to a later TGV to Montpellier. From Montpellier, you'd get a train to Carcassonne. This is the route JoLui has suggested.

It’s long, but lovely looking out the window and going through so many geologically distinctive regions. The train is an old single-level model and gets up to the TGV speeds we are used to from time to time.

A good first stop for you would be Besançon or the capital of Burgundy, Dijon. A second stop could be Montpellier. But if you do it with only one overnight, stop in Lyon. It's all old, stone and highly photographic. Sometimes it's even quaint.

I don’t know anything about your next leg, but if I were doing it, I’d check if I could fly direct flight to Rennes from Toulouse and then decide between train and plane.