As a Spanish resident
As uncertain as the situation is at present, it is wise to check and review some aspects of your life in Spain before Brexit is finally implemented (if that actually happens). We would recommend checking your Spanish documents to see if they are all up to date.
- Padron registration
- Tax registration
- Social Security registration
- Car registration
- Health Services registration
- NIE number
With regards to your Will, you can still enjoy the benefit that Brussels IV offered in terms of deciding that UK Law should govern your inheritance instead of your country of residence. Once Brexit happens on 29 March 2019, the old rules relating to International Private Law forwarding will possibly be in force again and then you may be forced to be under Spanish Law even if you are a UK National (if you own just one property and that is based in Spain). So, the advice is also to do a Brussels IV Will before Brexit is finally implemented.
If you are a non-resident in Spain
Our best advice is to start the residency process before Brexit, as those existing processes may possibly be respected and you could acquire rights according to Law governing the situation before Brexit.