Studying free-ranging marine animals is a daunting task due to their life style. This challenge promoted in the past two decades an unprecedented revolution in the use of technology to study moving animals, led by engineers and biologists, which gave rise to the emergence of biologging. Nowadays, researchers working with many different taxa -from species moving in marine to terrestrial to aerial environments- take advantage of biologging to study animal ecology. Nonetheless, seabirds are probably one of the animal groups where the use of biologging has had the greatest impact in advancing the knowledge of their ecology. In this talk, I will illustrate how biologging can help advancing the study of the ecology and conservation of seabirds, showing briefly several studies carried out in two pelagic species breeding in Spain, the Cory’s and the Scopoli’s shearwaters, addressing topics such as foraging ecology, migratory movements, behavioural landscapes, spatial consistency, Marine Protected Areas or fisheries interaction.