My wife and I both used our Sprint phones in February. They worked well in Cancun, Playa, Puerto Adventurous, and even at the Barcelo Maya, where we stayed. You definatly have to activate the international roaming by calling customer service before you leave. Coverage also depends on the type of phone you have, single band, duel band, or Tri mode phone. Sprint can tell you based on the model info you provide. We both have the tri-mode phones which allows the phone to work on more systems Sprint has roaming agreements with. As posted above, it is $4.00 a month to add the international roaming "plan", which can be cancelled at o charge upon your return. Signing up for this "plan" does not effect how and where your phone works, but it does bring the cost from $1.00 a minute to $.70 a minute. If your going to use the phone for 15 minutes or more it simply saves you money. We also bought the telmex LD card which works great from a pay phone, but the cost savings were not enough to out weigh the convienance of the cell for us. Hope this helps.