This is an important point to prepare before departure.
Imagine you have €30,000 in savings in France.
There is no need to transfer the entire €30,000 to your Vietnamese account immediately.
You can keep most of your savings in Europe and transfer gradually what you need.
For example:
Main savings → Europe
↓ transfer when necessary
Vietnamese account → local expenses
This also limits your exposure to EUR/VND fluctuations.
Always compare the total cost of a transfer: fixed fees + any intermediary fees + the actual exchange rate applied.