ローミングとeSIMの比較

Why was I charged on landing day with data roaming off?

October 26, 2026
4 min read
Graba SIM Team
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Data off is not line off

Roaming off blocks a data session. It does not block every home SIM event.

You can be charged on landing day with data roaming off. That switch only stops the home SIM from starting a mobile data session. It does not stop the SIM joining a foreign tower. It does not stop incoming calls you answer, texts, or voicemail diverts. Some networks start a daily product on one of those events.

The short answer

If you were charged on landing day with data roaming off, check registering, calls, texts and voicemail, not only maps. Turn the home line off when you do not need the number.

Why This Matters

The phone feels safe because the data switch is off. The home line can still be seen by the network for calls and texts, while the travel eSIM carries data.

Events that ignore the data switch

Registering happens when the line is on and searches for a network after the plane lands. Data roaming off does not hide the SIM. Incoming texts can still arrive. A call you answer uses the home line. An unanswered call may go to voicemail on the home account. On some plans, each of those can be the trigger. Allow Cellular Data Switching, or Android Auto data switch, is separate. With it on, a weak travel signal can send data through the home SIM, even when data roaming looks off on that line. Turn the back-up off and select the travel eSIM for mobile data.

What to change before the next landing

Install the travel eSIM on airport Wi-Fi and set it as the data line. Turn its data roaming on, and turn data roaming off on the home SIM. Turn the back-up switch off. If you do not need calls or bank texts on the home number that day, turn the home line off until you do.

What data roaming off does not block
EventBlocked by data roaming off?Typical control
Home SIM data sessionはいKeep it off
Registering on a foreign towerいいえLine off
Incoming textいいえLine off or a bar
Call or voicemail divertいいえLine off, voicemail off

Travel data does not explain the home fee

Graba SIM use on the travel eSIM is a separate line in your holiday spending. A home-network daily product can be charged the same day for something that is not data.

Illustrative example: Roaming off, pass on

Leo turns off data roaming on the home SIM before take-off and uses a travel eSIM for maps. On landing his network texts him a daily pass, while he is still queuing at passport control. Support says that joining their partner network started the product. Data roaming was off all the time. He turns the home line off for the rest of the week, except two evenings when he expects a call.

Landing day without home data

  1. 1 Land
  2. 2 Line on
  3. 3 Non-data event
  4. 4 Home charge
Data roaming off stops data sessions. Registering and calls can still be billed.

Final Thoughts

Treat data roaming off as one switch in a set. For registering and calls, you need the line off or a network bar.

Read next: the full roaming switch list, home daily pass versus Graba SIM day pass, the main guide in this series.

Set all four switches before landing

Walk through the data line, the roaming switch for each line, and the back-up switch, so landing day is no surprise.

Open roaming settings

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