Internet and cell access in Spain

I use the hotel WiFi when at it. Other than very remote locations cell service has never been an issue. I will add that I seldom make a call and only use my phone for navigation while out seeing the sites.

There is a TON of information in this forum - under Technology - on SIM cards, eSims, etc.

I tend to take the contrary - and lazy - view, and just include the cost of international cell service into my travel budget. It's simply the easier, if more expensive, option. I don't want to waste time looking for wifi if I need a map, or an app, or want to look something up, or worry that I can't get a 2-factor notification or a PIN, and so on.

If you are Verizon, they have a new plan called Unlimited Ultimate (they really are running out of names for their plans lol) that actually includes international data/text/calls, for $55/month. I just signed up for it (it wasn't much more than I was already paying, plus I'll get iTunes for less than I am currently paying).

Prior to that, I used their international plan, or their TravelPass plan (pay $10/day but only if you actually use cellular).

T-Mobile has worked seamlessly for me so far. https://www.t-mobile.com/cell-phone-plans/international-roaming-plans?country=Spain

We just returned from 2 weeks in Spain. Madrid, Toledo, Cordoba, Seville, Granada, Valencia, Barcelona. As usual when we are in Europe for more than 10 days, we just added the Verizon $100/30days international plan. Never had a connection issue. Easy Peesee lemon squeezy....