The current study presents the results of the activity of radionuclides in spa waters, and evaluates their radiological influences on the population consuming these waters in the Central and Eastern Black Sea regions of Turkey. Since these waters are used for therapy and consumption purposes unconsciously, their radiological impact on the people was computed by taking into consideration the annual intake through ingestion of Ra-226, Th-232, K-40, Cs-137 and Rn-222. The mean activities were estimated to be 11.35 for gross alpha, 6.23 for gross beta, 2.96 for Ra-226, 0.42 for Th-232, 0.069 for Cs-137, 0.19 for K-40, and 267 Bq L-1 for Rn-222, respectively. The estimated effective doses from spa water were found to be 49.77 mu Sv a(-1) (Ra-226), 5.95 mu Sv a(-1) (Th-232), 0.07 mu Sv a(-1) (Cs-137), 0.83 mu Sv a(-1) (K-40) and 56.03 mu Sv a(-1) (Rn-222). These values were evaluated and compared with related verified values from literature. Also, physico-chemical characterizations of spa water samples considered in the current study were investigated. This study would be useful for consumers and official authorities for the assessment of radiation exposure risk due to usage of the considered spa waters.