Foreigners entering Portugal through a border not subject to control, for example, those coming from Spain by land or from another European country not subject to passport control, are required to declare this fact within 3 working days from the date of entry at the Portuguese Immigration and Border Service.
The following foreign citizens are exempt from submitting the declaration:
• Residents or individuals authorized to stay in the country for a period exceeding 6 months.
• Those benefiting from the community or equivalent regime.
• Those staying in hotels or similar establishments.
Failure to submit this declaration may result in a fine of €60 to €160.
To learn more about the declaration submission, please refer to this link.