Eleven subspecies of the White Wagtail (Motacilla alba) are currently recognised and they all have slightly different plumages.
This is Motacilla alba alba, the nominate subspecies of the White Wagtail which occurs on the European continent and migrates down as far as Kenya.

1st, 2nd & 3rd photo: Arrimal, Serras de Aire e Candeeiros Natural Park, Portugal, 10 October 2021
4th photo: Alcobaça, Leiria, Portugal, 11 October 2021
5th photo: Choupal National Forest, Coimbra, Portugal, 9 June 2023