There are regular and frequent connections from Paris to Nantes by high speed train (TGV). Leaving from Paris Montparnasse station, the journey takes on average 2hrs 30 minutes.
All seats on TGV trains are numbered and must be reserved. Prices vary depending on the time and day of departure and you are strongly advised to book in advance in order to take advantage of the cheapest fares. For example the cheapest one-way ticket is currently available at 15€, whereas a ticket bought on the day will cost a minimum of 85 €.
A number of low-cost coach services arrive in Nantes from Paris and other major cities such as Bordeaux and Toulouse. These services offer quite comfortable travel with free-wifi, air-conditioning and on-board toilets. The journey from Paris takes around 5 hours. Fares vary depending on your day and date of travel, so advance booking is highly recommended. If you arrive by coach, your journey will end at Haluchères. From here you can take Tram Line 1 to the city centre.
For more information about coach schedules and fares see: