Tracking data of 10 harbour seals and 2 grey seals were obtained from the deployment of GPS Argos Satellite Relay Data Loggers (SRDLs) developed by the Sea Mammal Research Unit (UK). Full tag description is available at: http://www.smru.st-andrews.ac.uk/Instrumentation/GPSArgosTag/. The tags include a wet-dry sensor from which haulout events are recorded, a pressure sensor providing detailed dive data, as well as a GPS recording irregular locations when the seal is not underwater. Data is stored onboard and transmitted by satellite via the Argos system. The data provided here are both the individual GPS and Argos locations of the seals fitted with these tags for an average duration of 145 days.