travel from Rome to San Sebastian

Unfortunately, San Sebastian is not that big a place, so direct air links are non-existent....only Iberia, I believe, links to Madrid so, without any competition, charges are very high. Your best bet might be to fly a discount airline to Barcelona (clickair, vueling, Air Europa) then take a train to San Sebastian. There are 2 a day from Barcelona, 640 am (6 hours) and 1230 pm (8 hours). Tickets from 16-58 Euro. Or fly to Madrid (vueling, Air Europa) and take the train from there. Three a day, each around 5 to 5.5 hours...740 and 8 am, and 410 pm..rates from 20-59 Euro.

Thanks for your advice. I'll check in to it.
Lori

Lori, you'll have to do some checking, but see who if anyone goes Rome to Biarritz/Bayonne airport in France. From there it's just a short hop by train/bus/taxi across the border to San Sebastian.

Lori, I checked and Biarritz-Bayonne won't work from Rome. Bordeaux will and it's a shorter train trip to SS than Madrid.

Thank you everyone for your helpful advice. You've given me some options to check into.
Lori

Thank you Geoff. I'll check it out!
Lori

Looks like Iberia is charging roughly €250 round trip for a direct flight. On the bright side, their habitually surly customer service, lost luggage, incessant delays and undeclared pilot strikes are included in the price.

I just did a quick check. Clickair flys from Rome to Bilbao via Barcelona and return. From Bilbao there is a bus that leaves from the airport to the bus station in San Sebastian.
For the dates selected for this test the cost round trip is 240.00 euros and there is a layover of a few hours in Barcelona.
Veuling doesn't fly Rome to Bilbao. You might check Spanair.com.

Good luck

Just to comment on the last part of your posting, "Is the train a better alternative?" From Rome, no....it'll take you a day or more to make that journey.

My husband and I are planning on doing the same exact thing (flying from Rome to northern Spain) in March. We have spent hours on planning. What I think that we're going to end up doing is to fly from Rome to Santander on Ryanair. We will likely stay 1 night in Santillana del Mar, go to Bilbao for 1 night, then go to San Sebastian. The flights on Ryanair to Santander can be as cheap as 19 euros depending on what day you go. If you do not want to stop in cities in between, the FEVE train takes a little less than 3 hours from Santander to Bilbao and from there it is a 1.25 hour bus ride to San Sebastian.