Best way to get from San Sebastian to Barcelona

Have a look at the Renfe site. It mentions a direct early morning train (7:28) which brings you to Barcelona in around 6 hours for some EUR 45.

I don't know when you're traveling. I randomly checked skyscanner.com for one day next week and found a $45 non-stop Vueling flight at 7:40 PM from the San Sebastian airport (near Hondarribia) to BCN. Hondarribia itself is a very interesting town; I don't remember whether the (rather frequent) buses to Hondarribia all stop at the airport, but they may.

Rome2Rio.com coughs up these additional options:

• Lurraldebus or Transportes Pesa bus to Bilbao airport (it says hourly, duration 75 minutes), then fly. I think this would be better than taking a train to Bilbao and having to scramble transportation to the Bilbao airport even if the train were as fast (it's not; see below).

• Train via Zaragoza. There's a weekday 7:28 AM ALVIA departure arriving in Barcelona at 1:20 PM. If you bought it today for October 17, you'd pay only €42.

Rome2Rio doesn't suggest the train/flight combination at all. I think the only train between Bilbao and San Sebastian is the scenic (it's a very nice ride) but slow Euskotren. The bus is much faster, and--if Rome2Rio is to be believed--it will take you straight to the airport.

I'm not fond of mixed-mode trips, especially when a flight is involved. If the non-stop SS-Barcelona flight didn't fit my schedule, I'd be looking at the train, or--if every minute counted--I'd delve into the schedule details for the bus/flight combo. By the time you build in check-in time and getting into Barcelona from the airport, it seems unlike that the bus/flight combo would save more than a few minutes off the train time.

You can check the Deutsche Bahn site for other train options, most of which are slower and/or require a change. I used Barcelona Sants as the destination.

The "best" way varies from person to person - fastest, cheapest, arrival time, etc. There are typically 2, direct trains per day from San Sebastian to Barcelona, taking about 6 hours (one in the morning the other in the afternoon). A full-fare ticket is €83 while advance-purchase tickets are as low as €33. See www.renfe.com for schedules and tickets. Most of the cheapest advance-purchase tickets are non-refundable, non-exchangeable, so you should be ready to commit at time of purchase.

There is at least one direct flight per day on Vueling Airlines, taking 1 hour. Looking at a random day in mid November, I see a flight for €40. See www.skyscanner.com for options. This particular day, the flight departs S. Sebastian at 7:40 p.m., so if you wanted to get to Barcelona earlier in the day, the morning train would be the best way, getting you there by 1:30 p.m.