❌ Only using your French plan
Roaming can become extremely expensive.
❌ Randomly buying a SIM card in a tourist shop
Prefer an official operator or reseller and ensure that the line is properly registered in your name.
❌ Regularly changing your Vietnamese number
Once your number is linked to banks and local services, changing it becomes cumbersome.
❌ Immediately canceling your French number
You might still need it for French accounts and services.
❌ Only using the apartment's Wi-Fi for work
Keep a 4G/5G backup solution.
❌ Neglecting the security of your smartphone
Your phone can gradually contain a large part of your Vietnamese digital identity.