sim cards

This thread explains how to get one in advance. Should be good in both Spain and Portugal.

https://community.ricksteves.com/travel-forum/tech-tips/dutch-vodafone-sim-card-for-use-in-europe

Yes, the Dutch Vodafone SIM I wrote about on that thread should work fine in both countries - for data. For local calls and texts to Spanish and Portuguese numbers? Perhaps not so much. (I used my Vodafone SIM only for data.) It seems that you get only a limited number of call minutes even to Dutch phone numbers (from anywhere in the EU) and perhaps none to other EU numbers. (Incoming calls and texts should be free though, as is the standard for European prepaid phones.)

(Use Google Hangouts if you live in the US and need to make free calls home, even to landlines.)

Also, I've read that the Dutch Vodafone SIM may not technically allow use as a hotspot...but they can't block it on Androids for some reason (I used my Android as a hotspot to use probably half of my 2G of data over 2.5 weeks - I needed it!). Not sure if iPhone would allow use of hotspot with it or not.

There are also UK SIMs one can buy ahead of time that may have different restrictions but perhaps more data. But make sure you can add credit to them online - you may need to use Paypal for them.

Vodafone has tourist plans including calls and data for €20 for 30 days. It will also work in Spain. You can reserve one for pickup in the arrivals area of either Lisbon or Porto airport. Just make sure your iPhone is unlocked otherwise it won’t work. If you can’t find out from your carrier if the phone is unlocked, you can call Apple and they can tell you.

I know your question was a month or so ago, but I had to jump in since I didn't see an answer I was expecting.

I travel to Europe several times a year from the US on business. (AT&T iPhone). I long since gave up on using local sim cards as they simply aren't needed (at least not for me). Almost all the carriers in the US now have international add on plans that are fairly reasonable. Mine with AT&T it simply charges me $10 on any day I use data (or voice). If I don't use data then there are no charges for that day.

I usually I turn my data off and then turn it on if I need it when away from Hotel Wifi. At worst it cost me $10 for the day. I know Verizon has a similar plan and I think Tmobile has free international free data. So generally I think you can get something reasonable cost. It isn't like the old days when you roamed and had a $800 bill accidentally. There are other plans as well which gives me smaller amounts of data (like 200MB) for $40 and etc. That makes sense if you absolutely need to use data off of wifi everyday.

So what I'm saying is to me it doesn't make any sense anymore to run around and try to find a local sim card. You also have to get your phone unlocked before you leave to be able to use the local card.

Local sim cards were essential when the US carriers didn't have reasonable international add on's up until a couple years ago. For a two week trip and making an attempt to stay on wifi if at all possible i usually end up with about $60 or $70 in charges. And for that I have full use of my phone, voice calling, data, text and voice mail. (When I used local sim cards, i was always having to try to retrieve my phone voice mail long distance anyway and incurring charges).

I will admit you may be able to find some cheap options like local sim cards that are discussed for $20 or $30.. I've done that and if you are really and truly on a very thin budget then I get it. usually they cost me more than I expected... But to me the hassle far exceeded the convenience of just using my US carrier with add on plan.

That said I'm more of a business traveler and not ultra sensitive to a few bucks more in exchange for much more convenience and one less headache and distraction.

Good luck and enjoy your trip.