Calling/texting my travel partner while abroad?

I'm traveling with my boyfriend to Europe. We want to be able to text or call each other if we accidentally get separated. I'm not concerned about the monetary rate - I just want to know if it'll work. I've heard you need to get international activation (get it "unlocked") to even use your phone while abroad, is that true? That's what I'm concerned about.

Do you also need international activation to access the internet from your phone? (I know the data is expensive without a plan but will it still work?)

If it matters, we both have iPhone 5 and we're together on the same AT&T plan. We'll be in France, Italy, and Switzerland.

If this is something we need to get done, do we go to the Apple store, or to AT&T for it?

Maybe walkies-talkies would be cheaper.

Yes, you must have an unlocked phone and must have the calling card of the appropriate country. You can buy a cheap unlocked foreign phone over the internet. Arrives in a week or so.

Depending on your plan, you'll need international voice and data services activated. A call (or visit) to the AT&T service center should take care of that.

There might be a problem with LTE (4G), though. If you can't find a network, you might try switching LTE (4G) off on your phones. Apparently, the US version of the iPhone5 can become confused if it's in range of a European (German) LTE base station and refuse to book into even an (available) GSM network.

As for 'I'm not concerned about the money' - better think about it and/or ask AT&T at least about the cost for a european data roaming package (if they offer something like this). Otherwise, your bill could easily go up into four figures… Or switch off data roaming (is off by default) and/or cellular data on your phone.