I'm going to panama for a month, and i don't want ANY iphone overseas fes?

So can i just take out my sim card and use Wi-Fi. I NEED TO KNOW As soon as possible.

You can go to settings, then carrier, and turn off automatic.

AND/OR (do and) Go to setting, turn on airplane mode. Wi-Fi will turn off initially. But you can go into Wi-Fi and turn it back on. The mobile network will be disconnected completely. Only Wi-Fi will be available.

Remember, you need to manually turn Wi-Fi back on.

Taking your sim out will also work, but it is not necessary.