Just like in the case of Greece a few days ago, the reason is that the authorities want to have the whereabouts and contact details of travelers in order to know exactly which tourists are where in the country in the event of possible random checks or renewed lockdowns. It is known to be difficult for sailors because they are mobile on the boat.
The new Android health app from the Spanish authorities
For this, personal data must be registered, either on the website provided for this purpose or on viApp. However, the SpTH app is so far only available for the Google Play Store for Android, the Apple version has not yet been completed in the App Store.
If you have registered via one of the channels, the traveler receives a QR code that must be shown upon entry. If you do not have it, you have to fill out the form afterwards when entering the country, and longer waiting times are to be expected.
The questions asked include the last place of residence, previous trips to other countries, the length of stay there and the address of the accommodation. Name, home address, telephone number, age and ID number must also be entered.
When entering Spain, there are temperature measurements, and according to the information on the QR code, it will be decided whether a corona test will be ordered as a precaution or not. There are currently some new corona outbreaks in Spain, but mainly on the mainland, not in the Balearic Islands, which have already come through the crisis with very low numbers of cases.