The link above is accurate. We're sort of all correct. If you have a dumb phone with international calling turned on, you will be charged for voicemail even if you don't answer.
With iPhone visual voicemail is a data plan. Your voicemail is sent via the data plan and stored on your phone. So with data off you get the solid red circle and no message. And I think ATT treats it as if the phone is off and hence no charge. It's been a long time once I travelled w/o data, so I'm a bit fuzzy on the following : turning wifi on wont deliver the voicemail, but tapping the red circle will and then you may be charged. Not sure.
But with data on you will be charged for the voice minutes.
Att does make mistakes. For almost 2 years I was never charged for sending text while roaming!
With iPhone visual voicemail is a data plan. Your voicemail is sent via the data plan and stored on your phone. So with data off you get the solid red circle and no message. And I think ATT treats it as if the phone is off and hence no charge. It's been a long time once I travelled w/o data, so I'm a bit fuzzy on the following : turning wifi on wont deliver the voicemail, but tapping the red circle will and then you may be charged. Not sure.
But with data on you will be charged for the voice minutes.
Att does make mistakes. For almost 2 years I was never charged for sending text while roaming!