We are considering a trip to Croatia and Italy next spring. I would like to bring along my 3rd generation AT&T iPad. I have never activated a data plan for it. What I already know is: I will not have 4G LTE service in Europe with my U.S. iPad. I can live with that. I can activate a roming data plan with AT&T, but it is quite expensive ($30.00 a month for only 120MB). I can buy a SIM in Europe (or by mail from here, apparently) but this only works on an "unlocked" iPad. What I don't know: Whether my iPad is "locked" or "unlocked." Surprisingly, even the companies that sell these SIMs don't explain how you know. Purchasing a SIM seems like a game of chance. Different providers, different coverage, different costs, 3G vs. 4G, questions about whether they will even work, etc. I found a couple of sites that sell SIMs online, but they seem kind of sketchy to me since they don't really explain much of what you need to know. Can any of them really be trusted? I've seen recommendations for buying a SIM when you get to Europe. But how would I know where to buy, how much to expect to pay, or even whether it would work if I did buy one? I've read many threads on this topic but don't find a clear answers to my questions. FWIW, most nights will be spent onboard a cruise ship, where I don't expect to get cell coverage (and where wifi access is not provided). So the data plan would be mainly for use in the ports of call. Thanks!