The 12-year-old had used his phone to unwind and watch a few videos while at sea between Germany’s northern city of Kiel and Oslo.

Shortly after he came home from vacation, a hefty bill from the family’s telecommunications provider arrived. It stated that about €12,500 was due for usage of just under 500 megabytes of data while at sea.

The boy apparently connected to the cruise ship’s own phone network which connects to the internet via satellite, said Dirk Hundertmark, managing director of Norwegian cruise operator Color Line.

The network is only really intended to be used by the ship’s crew to communicate with other vessels, even though anyone can join it. Similar to aircraft, high roaming charges apply when using such networks.

Cellular phone networks in Germany can charge as much as €30 per megabyte of data downloaded through a satellite connection. At sea, the EU’s abolition of roaming charges does not apply.

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Color Line has said that it tries to inform passengers on its website about possible roaming costs. The cruise line operator also offers wifi packages on board for certain fees.

“This is really an extreme case that the family has experienced,” said Hundertmark.

It is very rare that passengers dial into the satellite network unnoticed, the managing director added, stating that they would be informed beforehand from their provider via SMS about possible costs.

As a gesture of goodwill, the phone network has agreed to reduce the family's bill to €5,000, reported broadcaster NDR.

But the Berlin-based family has since employed a lawyer in an attempt to take action against a bill which they consider to be “immoral.”

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