Are the Verison minutes good for international use? Most of the time those deals are for domestic use or they use more than one of the minutes credit for each minute actually used. They want their money one way or the other.
Onboard rate is the same as international. Depending on the carrier it is $2 to $2.50 per minuet. If you are in a non US port you will pay a high rate as well.
When in Grand Cayman I pay about $2.50 on my cell. If there is internet access I can use Skype for about 2 cents per minute, a slight difference.