I was just in Cabo and had called Verizon in advance to make sure my cell phone would work there. Even though they assured me it would and said they had activated my "international" calling, the phone did not work. I could not dial out at all.
A word of warning - do not use the pay phone at the airport (probably anywhere else). Our flight was changed and we had to make several calls to make pick up arranagements. Each call ended up being $42 each, probably not more than a minute phone call!!! We found over $200 worth of pay phone charges on our credit card when we got home.