Paperwork and public services
IBAN (International Bank Account Number)
In short
Your bank account number in a format every bank accepts, so money can be sent to you or paid from you.
An IBAN identifies a bank account in one standard format. Public services ask for it when they pay you an allowance or a tax refund, and employers ask for it to pay your salary.
In Greece an IBAN always has 27 characters. It starts with GR, followed by 2 check digits, 3 digits for the bank, 4 for the branch and 16 for the account. If one digit is missing or extra, the payment will not go through.
Anyone who accepts SEPA payments from domestic accounts should not reject your IBAN just because the account is in another EU country. If that happens, you can complain to the competent authority.
Official source: Bank of Greece