I need to get from Barcelona to Lisbon by rail in a couple of weeks. I know it's not a good, reasonable route. That doesn't matter. Online sources I find all conflate rail with buses. We can't do that. We might need to go by way of Madrid and/or Toulouse and/or Bilbao and/or the Algarve! Time is immaterial. Rail travel is Essential. I'm eager for any route suggestions, to avoid just showing up at Barcelona Sant and trusting to luck.
The man in seat 61 shows several options here. See his options for London to Lisbon via Barcelona. You could just follow his plan starting in Barcelona. It won’t be quick:
https://www.seat61.com/Portugal.htm
Hi Peter. On bahn.de website, you can specify mode of transit as rail only; it shows several options; shortest is about 16 hours.
I did this once on the reverse direction. You could do Barcelona - Santiago de Compostela. Spend a day there, then go to Vigo, continue to Porto and then to Lisbon.
The Algarve is not an option. There is no rail service from Seville, etc., across the border into Portugal. Folks who go that way have to cross the border by bus (or rental car, etc.)
Or there is still the short international ferry route across the estuary(a short ride? from the southern tip of Spain to the end of Portugese railways, for the slow local trains through the Algarve.
It's a short local bus ride to the ferry from the last station in Spain.
Several connections in Spain from Barcelona, so a bit of an overland adventure, but certainly an interesting way to do the journey.
If time is immaterial and you want an overland trip then go from Barcelona to the French border at Hendaye, then make your way along the coastal Spanish narrow gauge (2 to 3 days) ultimately to Santiago de Compostela. From there the last day is to Lisbon changing at Vigo and Porto.
You can get to Hendaye by 6 different routes - two via Madrid (there is still the old slow line from Barcelona to Madrid), four by differing routes up into France, and not all itemized by the Man in Seat 61.