Is there any secure way to transfer data between mobile phones without Internet?

Assume that I don't have any Internet access in my country. The only thing that I have is a mobile phone with a 3G or 4G SIM card inside. The mobile operator didn't provide any Internet access also.

Now I want to send a some data (Text/Voice) to my friend in another country. Is there any way? How I can do it?

And if I want the communication to be secure, what shall I do? I mean I don't want to anybody be able gain the data, except my friend. is there any way? If so, how?