Telephone numbers in Austria have no standard lengths for either area codes or subscriber numbers, meaning that some subscriber numbers may be as short as three digits.

Larger towns have shorter area codes permitting longer subscriber numbers in that area.

Prefix code with 0 when dialed within Austria: In ascending numeric order: Due to Mobile number portability, the code is not an accurate way to determine the provider of a mobile phone number.

The providers assign only in exceptional cases (special sort of custom numbers, more expensive) non-existing numbers with a different prefix, and this is handled similarly to porting an existing number from the desired network.

However, the providers still have administrative sovereignty over their own prefixes.