Booking trains from Barcelona-Madrid-Granada-Seville

Rob, you beat me to it. We are also heading to Spain this year, and will have several train trips. I've been seeing conflicting information about when to buy tickets, how soon, and from whom. I had decided to post on the ever-helpful Forum, but here you are!

I think the best strategy regardless would be to download the Renfe and Iryo apps so you can keep an eye on any routes and see how often they become sold out. There is a website called the Man in Seat 61 that gives good overviews.
As a rule, I book long distance high speed trains like you would take between Madrid and Barcelona in advance, as you get savings that way. The other (regional) trains are probably more likely to sell out so I would check your dates against any holidays.

Use this company for Barcelona to Madrid
https://iryo.eu/en/meetus/we-are-iryo

Madrid to Granada
https://www.renfe.com/es/en

Seville to Granada
Just take the bus
https://www.alsa.com/en/web/bus/home

There are four train companies in Spain offering high-speed train tickets: Renfe, the government-run national train company, Renfe’s low-cost subsidiary company called Avlo; private train company Iryo. and Ouigo España, a subsidiary of France’s national train company, SNCF.
All four train companies have their own websites, each of which displays the train schedules and ticket prices for that single company.
There also are a couple online companies which contract with the four train companies and display their schedules and also sell their train tickets: www.TheTrainline.com and www.Omio.com are two of the most reputable companies doing this.
If you want to compare train ticket prices among the four different companies— you need to go to one of the websites that sells the tickets of all four companies. Renfe, for example, is not going to show the price of its competitor’s train tix and it’s also not going to show you any of its competitor’s schedules.
Renfe’s STATED TIMEFRAME as to when it sells its train tix is 90 days in advance of the train’s departure date for its high-speed trains. But Renfe fails to follow this timeframe and is notorious for putting its high-speed train tix up for sale online whenever it gets around to doing it, This has been the case for years, and it seems as though this will continue indefinitely. Renfe’s been known to put high-speed train tix on sale online just a few days before the train’s departure date. This is a source of frustration for foreign travelers wanting to finalize their vacation plans and pre-purchase their train tickets for their itinerary just as they do for their flights and accommodations.
The good news is that the private company, IRYO, puts its high-speed train tix on sale up to 12 months in advance. And IRYO’s routes include Madrid to Barcelona/Zaragoza; Madrid to Cordoba/Seville and a few other cities such as Valencia, Malaga, Cuenca and Alicante. You can see IRYO’s routes and buy tix at www.IRYO.eu/en
The train routes from Seville to Granada and Granada to Madrid are currently serviced exclusively by Renfe. Consequently, ticket prices are quite high.
As already pointed out, frequent Alsa buses do the Seville-Granada route for about 30% to 50% of the cost of the Renfe trains while only adding 20-30 minutes to the journey.

On some Renfe trains you can opt for an "Elige" ticket that is a bit more expensive than the basic fare (which can be quite low if you buy your ticket super early) but offers some changeability/refundability features. If you do need to change a ticket, you will always have to pay the extra cost of the new ticket, based on then-current pricing. If you make such a change quite some time after the original purchase, that extra cost could be substantial. Look carefully at the Elige rules for tickets you're considering, and check prices for those same tickets for immediate travel (same day or next day) so you know what sort of money you're dealing with. That research will also allow you to see how much money you will save by taking the risk of buying tickets shortly after they go on sale, when their prices are at their lowest.

There is some good information here. Thank you!

Has anyone had experience with IRYO? I'd like to book a journey with them now, rather than wait another 3 months for the Renfe seats to be available.

Trainline.com does show Renfe tickets available now for early October dates. How reliable would that be this far ahead?

We took an Iryo train from Barcelona to Madrid. Iryo uses high-speed Frecciarosa ( “Red Arrow”) trains used in Italy by Trenitalia. Bought the ticket months in advance for $22 and the train was new, clean and extremely comfortable.
Renfe uses AVE trains which are fine. Best thing to do is just buy the ticket that works best with your itinerary and offers the best price. If Trainline is offering the ticket, everything should be fine. You might be able to save a couple Euros booking directly with Iryo or Renfe once you’ve figured out which train you want,
Have a great trip!

Thanks, Kenko; that's just what I wanted to hear.

All of these suggestions have been very helpful. Thanks to all of you who took the time to respond to my post. I really appreciate it!

We, and many others, found renfe.com frustrating to use. We ended up using trainline.com which also has the advantage of listing all of the other competing train companies at the same time which made it easy to compare and buy. Trainline was much easier to use and we saved a lot of time and grief. Any price difference was insignificant.