Swiss Train Travel during Holidays

Swiss trains tickets do not work the same way as your Paris to Geneva ticket.

• You buy a ticket and it is valid for any train on the date shown on the ticket (usually the date you buy the ticket on).
• In most cases there is no discount for advance purchase. No reason to buy in advance (there are some advance-purchase discount tickets on some routes, for simplicity I won't mention them).
• Tickets cannot sell out, because they are not specific to a train.
• All routes have at least one train per hour, most have two, including Geneva - Luzern and Luzern - Basel.
• Trains run 7 days a week, 365 days a year to (nearly) the same timetable.

Are you going from Geneva to Luzern the same day as you travel from Paris to Geneva?
Are you going from Luzern to Basel and on to Paris on the same day?
If yes, you DO NOT need to buy two tickets. Just buy one ticket, Paris to Luzern via Geneva, and Luzern to Paris via Basel. Simpler and possibly cheaper.

Do what the Swiss do, just turn up at the station when you feel like it, buy a ticket at the machine and get on the next train going in the correct direction - simple.

Look up train times on the SBB website: https://www.sbb.ch/en

No. In fact, Swiss trains never "sell out". You might not find a seat, in which case you stand until a seat opens up. The website www.sbb.ch/en has icons on the schedule indicating expected loading for each train in the near future. If you are worried you won't find a seat, you can purchase a seat reservation for 5 CHF. So as far as ticket purchases go, buying far in advance gives no advantage over someone who buys a ticket while standing on the platform with their smartphone seconds before the train arrives, its all about the seat reservation.

If you want to get a discount by purchasing a "Supersaver" ticket, you can get a discount buying ahead of time. These are train specific, like airline tickets. You must ride the train shown on the ticket as it is not valid on any other train. Or you could buy a "Saver Day Pass". For a fixed price, you can ride unlimited trains on a given day. These go on sale 60 days before your intended date of travel and prices go up as your travel date approaches. Earlier you buy, the lower the price. They are nonrefundable.

Thanks so much for the info. We will wait and just buy tickets when we get to the station. I appreciate the help - I would have been nervous doing this without your help.