A business bank account is necessary when relocating or opening your company in Portugal — not only for obvious reasons but for bureaucratic ones, too.
To get the start of activity certificate, (which you will need when opening your Portuguese business), for instance, you must provide the details of your business bank account.
Failure to do so might lead to paying penalties, and the deadline is tight: only 15 days from the date of incorporating the company to the start of activity declaration and only five days to deposit the share capital. The more prepared you are, the better!