How do cell phones work from the ocean? — Cathy, Washington, Ill.
Marshall Brain Answered:
The thing about a cell phone is that it has to be inside a cell in order for it to work. In the middle of a cell is a cell phone tower, and it might provide coverage for an area four or five miles in diameter (depending on terrain, type of service, buildings, etc.)
So if you are on the ocean and near enough to shore (a mile or two) to pick up one of the towers on land, you can get reception. Or if you are on one of the cruise ships that has cell phone service, you can get reception. They put a mini cell phone tower on the boat and then link up to the phone system via satellite. Keep in mind that cruise ship service is incredibly expensive, like $3 or $5 per minute.
Otherwise, on the ocean, a cell phone is not going to work. You would need to use a satellite phone instead.
See also: How In-flight Mobile Phone Services Work