Transportation question: Spain Euro Rail pass or buy tickets seperately?

When is this trip? Did you check fares for the actual dates you plan to travel? Train tickets can be much cheaper if purchased well in advance.

I recall complaints on the forum about difficulties using a Eurail pass in Spain. You apparently have to obtain your seat reservations in person, in Spain, which could be a serious problem given that it's not uncommon for Spanish express trains to sell out. Reservations are per train, not per trip, so I believe you'd end up paying double when your trip requires a connection. I believe the charge is 10 euros per reservation. I don't know whether there are quotas for Eurail-pass reservations in Spain; they exist and can be a problem in France.

The Seat 61 website has some information about the Eurail Spain pass and also the Renfe Spain pass you mentioned; I cannot guarantee that the info is up to date, but that website is updated frequently.

https://www.seat61.com/train-travel-in-spain.htm#RailpassesforSpain

Renfe 10-trip passes for high-speed trains won't work for you as it's meant to be used only on the same route (ie BCN-MAD), More info : https://www.renfe.com/es/en/travel/prepare-your-trip/abonos-ave-y-largadistancia

The general consensus is NOT to use Eurail in Spain, because reservations are mandatory and cannot be done online.
I know nothing about Renfe's own passes.

Another reason not to use an Eurail Pass is that in Spain on many routes there are now multiple operators. The Eurail Pass however only covers RENFE.

Granada to Seville is about 2 1/2 on an Avant service. Price is 47,50, and as with all Avant services that price is the same regardless of when it is bought. RENFE is continuously upgrading their services, so by the time your trip starts there may be more services on that route.

The important thing to remember when looking up prices on eg. Trainline is that RENFE is known for only opening bookings a few weeks in advance. So if you are looking several months in the future you are not seeing all trains. To get an idea of what is usually available use a date in next week or so for research.

Thank you for all your kind response! The trip is from Dec 27 to Jan 2. Maybe it's too early to look at the tickets?

That's only 7 days. Do you have 7 nights in Spain? 8 nights? You're trying to cover too much geography on such a short trip. I love Andalucia, but since your time is so limited, I'd recommend Madrid, Zaragoza and Barcelona. Or at the very most, Madrid-Cordoba-Barcelona. Even with three stops you're going to be spending an awful lot of time checking out of hotels, sitting on trains or buses and checking into hotels. Better to spend the time actually sightseeing.

Keep in mind that days are very short in late December.

I took a look at Renfe.com to see what Madrid-Cordoba and Cordoba-Seville options are available for Oct 26, Dec 28 and Jan 2. I found about the same number of Madrid-Cordoba trains (roughly 25) for each of those days, so I think Renfe has all the departures loaded. Whether all the cheap tickets are being offered at this point, I don't know.

The situation was different for Cordoba-Seville, with far fewer trains in Dec/Jan than this month (which shows about 35 trains); it seems all the trains south of Cordoba haven't been loaded for your travel period.

we have 13 days, but 7 days in this area (Cordoba, Granada, Seville). I have three days with train travel.

Spanish train ticket prices on Renfe trains fluctuate- so there is no set price for what a Barcelona-to-Madrid train ticket will cost. Prices will vary but the least expensive non-cancellable and non-refundable tickets for an adult in second class when bought when they are first released for sale can be as little as €15 for Barcelona to Madrid on a high-speed IRYO, Ouigo or Renfe train. You should check www.TheTrainline.com and www.Petrabax.com for the routes you want and consider getting open-jaw tickets for your transatlantic flight. so you can sequence your journey for optimal time efficiency:. This would be the routing with approximate cost in dollars of the lowest adult ticket price when bought up to 90-days in advance. ( IRYO sells its tickets up to six months in advance on its website). Barcelona to Madrid $16 Madrid to Cordoba $33 Cordoba to Seville $18; Seville to Granada ( AVE Train $48/ 3-hr Alsa bus $28; Granada to Madrid $38.
You may not see prices like these because, according to what Renfe claims, it’s high-speed train tickets first go on sale 90 days in advance and that was one month ago. Moreover, the most deeply-discounted Renfe tickets may be being sold 90 days in advance at Train stations in Spain without going on sale online. That may be one reason why so many travelers have reported buying online train tickets—even 40 days in advance—has been difficult as clearly not all Renfe’s train tickets are going on sale at the same time in both markets.

In any case, the fares for each adult at the lowest-possible single ticket price would be about $163. And that includes the seat reservation cost which comes free with the ticket. The kids would be $5 for each leg of the route, or $25 each. So, a ballpark estimate of the minimal total cost for all four of you would be $163 x 2 =$326 + $50.
Total = $376 versus RailPass cost of $560.plus cost of seat reservations.

Hi, all, just want to thank you for all your input! I finally booked all the tickets! I was so frustrated with renfe website in the beginning, put in our passport number numerous times! couldn't register an account, couldn't figure out how to buy 4 tickets together. Oh, thw worst is I downloaded the renfe app on my phone, registered an account, tried to buy tickets on app, and it led me to the website to buy tickets! OMG! Oh, anyhow, finally, I am a pro at booking on Renfe.
Here are my tickets (3 adults + 1 kid), why is a 15-year-old an adult in Spain????
1. Madrid to Cordoba, $109.60 total (all Euro, I just don't know how to type Euro)
2. Cordoba to Granada, $103 total (this one was funny I checked from 10 pm (California time) to 11 pm, it's always $28 for one ticket available, and the rest would be $56 each. I was like, so expensive! I started to think about renting a car, or other routes. Then at about 11:15 pm, I almost gave up, and started to add 4 tickets in (both on Trainline and Renfe, just to see the difference), suddenly, it changed to $28 each! However, Renfe didn't get through, and increased the price to $33 (acceptable I think), but Trainline can get through. I thought maybe trainline was holding up Renfe to release the $28 ticket to me. So I closed out trainline, waited for 10 minutes, back to Renfe, and checked out for $28 tickets! maybe in the morning of Spain time, Renfe will release some discounted tickets?)
3. Granada to Seville (haven't booked yet, only 6:50 am or afternoon train available, I will probably take a bus)
4. Seville to Barcelona, $247 total (the cheapest flight schedule is not good, adding up taxi to and from the airport, and luggage fee, it will still be more expensive than the train, and the train is always more comfortable than the flight.)

I'm glad you were able to get your tickets at mostly-reasonable prices. When your shopping cart shows multiple tickets for the same route, not all at the same price, I believe that means the cheap tickets are the very last ones available in the fare band, so the others cost more. Why the situation improved, I don't know.

It's not uncommon for the age-limit for children to be well under 18 on trains and in hotels. You'll probably find a different situation when you buy sightseeing tickets.

question for Madrid to Toledo: I was searching for train or bus on Renfe and Trainline for Dec 26. There was no train, and only limited bus. Is it too early to search for train? I checked several dates and found starting from Dec 10, there is no train available.

European train schedules get revised yearly on the second Sunday in December, which is Dec 11 this year.
Renfe is often later publishing new schedules. Check later; there should be trains, unless some engineering work is planned (unlikely).