•Translocated individuals had much larger territories in comparison with the residents.•The males and the adults were significantly more mobile than the females and juveniles.•The survival of the translocated individuals was 79%, main reason for death was predation.•Results can be used for better planning of the future translocations. The spatial behaviour of 47 European ground squirrels (Spermophilus citellus) was investigated through radio-collars in the frame of a conservation project for population reinforcement in south-eastern Bulgaria. For the first time both translocated and resident individuals were collared. After the release, each individual’s movement was followed hourly through triangulation during the day and the sleep sites were localised by radio-tracking in the evening. The results showed that the translocated individuals had much larger territories in comparison with the residents. The males and the adults were significantly more mobile than the females and juveniles. Considerable relocation was observed in more than one third of the translocated individuals between the 5th and the 10th day after the release. The main reason for death was predation. The survival of the translocated individuals at the end of the first active season after the translocation was 79%. Recommendations for future Spermophilus citellus conservation translocations were drawn.