The fastest way is flying. You can fly with Ryanair and various other airlines from El Prat (Barcelona) to Santander fairly cheaply. Your other option is going by bus (there are no trains), there are 5 a day, but that will take you 10 hours, and at 54 Euros single, it is quite possibly cheaper to fly too.
As for Santander to Limpias...you'll have to get a bus from Santander to Laredo (every hour, sometimes more frequent still, 4.15€) and then another bus from Laredo to Limpias (9 a day, 1.45€)
So not the easiest journey in the world, and probably too much to do in a few days holiday, you should consider whether it's worth missing out on what will be 2 days of your Barcelona trip to visit what is a very small and fairly uninteresting town! I imagine family connections are the reason though.
Anyway, hope that's helpful!
I'd like to update what I've said above, and remind myself I shouldn't write posts at 1am!!
The bus info was correct, as above. However there IS a train, but NOT from Barcelona! It still stands that there is no long distance train from Barcelona to Limpias, or Santander, unless you go via Madrid, which would take you ages. Once you get to Santander though (and the quickest way is indeed to fly), there is a FEVE train which will take you to Limpias, avoiding having to change in Laredo (as with the buses). However, the train station is not right in the centre, a fair walk out of town, and there are 4 trains a day, going out at 8am, 2pm, 7pm and 8.30pm, it takes about an hour and costs 4 Euros each way. Return there are trains at 7.30am, 9.45am, 2.30pm and 9pm.
You still wouldn't be able to do this in a day, but you could do it in 2 if necessary. If you're interested in the church and its christ, it's a bit of a walk from the river (its not always open however), but doable, there's a nice river walk with a rather strange and bedraggled open air naval museum, and limited explanations of the old port and there is of course the Parador, if you wanted a very luxurious stay for the night. This (and the town) is the other side of the river from the FEVE train station.
I say all this because I actually went to Limpias yesterday to check all this out!! Thank you for the impetus to go east!!
If you want any photos, let me know.
Thank you so very much for all the great information. I had been checking on the Internet different ways to get to get to Limpias and so far, you have been the best source. My husband and I had been thinking of making it a 2 day trip, just like you advised, flying from Barcelona to Santader, and after reading your reply, I'll look into taking the train to Limpias. I've been to most of the southern part of Spain but never to the northern part, and since I have read so much about the Christ at the church in Limpias, I want it to take this opportunity to visit Santander and go to this little town as well.
Let me ask you something else since you seem to be very good at this, do you think is worth it renting a car and drive back to Barcelona so we can see some of the cities of the northen region?
Again, thank you so much for taking your time to give me such good info. I would love to see pictures if you don't mind posting them.
Ok, well firstly, as I said before, when we were in Limpias the other day, the church was shut, and we couldn't get to see the Christ. I'm not entirely sure how to about the opening hours, without simply going to mass.
There is of course another option, if you wanted to get a couple of cities in, you could fly in/out of Santander (El Sardinero beaches, the seafront promenade, Magdalena peninsular, boat trips), then get the train to Limpias, and then get another train on to Bilbao from there (Guggenheim, river promenade, pinxos, old town, shopping), and then fly back to Barcelona from Bilbao instead of Santander (or in the other direction). That would get 2 great and different northern cities in, with the possibility of spending a night in each, and Limpias in the middle.
I wouldn't recommend the car option, it'll be a lot of driving, and it's quite expensive once you factor in tolls and petrol (it's about 9 hours drive or so). You'll spend so long driving you'll be rushing around and I think you could spend the time more constructively by just getting up north and travelling around up here.
I'll see how to go about photos, I'm not quite sure if I can attach them to a post to be honest!
Thank you so much RatonCantabria, you have been a great help and have provided me with really good ideas. And don't worry about the pictures, I know the feeling about not knowing how to download or attach pictures to emails. Anyways, thank you so very much; I'll discuss your last recommendation with my husband, I like this idea.