What do you need to do check-in at hotels in Spain?

For other countries, my experience was:

France: passport:no / credit card: yes
Italy: passport:yes / credit card: no

it depends.. photo i.d. ( passport) and sometimes a credit card but not always.

I would say check with your hotel directly before you get there, then you know. Not all hotels will ask for it, but some do.

I suspect the credit card requirement is going to vary by hotel, not by country. If it's a 1* hotel (or hostal) that takes cash only, the staff might not ask for a credit card. If it's a 5* hotel, the staff probably will.

Pleas tell me about that Italian hotel which didn't require any form of payment to check in; I think I may want to stay there!

Is that a serious question? I don't think any of the places I stayed at in Italy in 2004-2005 required me to show a credit card, although one of them had been prepaid.

Whether you need to show a passport or other identification document depends on the country's laws. In Italy, hotels must complete a form for the police and so normally ask for your passport. This requirement was abolished in France where hotels don't need to know who you are. I think Spanish hotels do need to record guests' details, but it only takes a moment for the staff to complete the form.
Whether you need a credit card is a matter for the hotel. Some hotels may want payment in advance if you're paying by cash, or they may want to keep your passport as security. If you tried to book into a hotel without a passport, credit card or cash, they would understandably be suspicious and
almost certainly refuse to let you have a room.

Every hotel in the world (of a certain standing) will require some form of "insurance" against your account, i.e. a credit/debit card. If you don't supply this then the likelihood is that you will not be able to charge anything to your room.

As for passports, if you're travelling from abroad you'll have one anyway, so this is a bit of a non-question really.

Something important in line with your question is that you need to be there personaly, they don't take phone or e-mails check in , only physical presence.
Hope it helps.

My experience in Spain is: passport and credit card

WillTravel:

Yes I was totally serious since I agree with M_Kingdom2's assertion that just most places (at least that I have ever stayed in) are going to want some sort of assurance that you are going to pay up, either by asking foir prepayment, or a CC imprint, etc.

I am certain there are some smaller establishments that will go on trust but even this past year when I stayed in about as small an "inn" in the UK as one could find they demanded FULL payment for all three nights when I checked in.