Ninety-six patients with sub-acute supraspinatus tendinopathy were randomized to receive a 3 week multimodal treatment program of transcutaneous electrical nerve stimulation (TENS), hot pack treatment, ultrasound therapy, and Codman's exercises with additional balneotherapy (spa treatment; n=48) or without balneotherapy (n=48). The outcomes of interest included range of motion (ROM) in flexion, abduction, internal rotation and external rotation, pain scores at rest, during sleep, and during movement on a Visual Analogue Scale (VAS), a shortened Disability of the Arm, Shoulder and Hand (QuickDASH) scores, hand grip strength, and Short-Form 36 (SF-36) quality of life sub-scores (i.e., vitality, physical function, pain, general health perception, physical role limitation, emotional role limitation, social function, and mental health). Outcomes were assessed upon completion of the 3 week treatment program. The balneotherapy group reported statistically significant improvements from baseline in all outcomes (p<0.05 for all). With the exception for SF-36 general health scores, SF-36 mental scores, and hand grip strength, the control group, too, reported statistically significant improvements in all outcomes from baseline (p<0.05 for all). The improvement from baseline was statistically significantly greater in the balneotherapy group compared to the control group for all outcomes (p<0.05 for all), except for SF-36 emotional-role and SF-36 mental health scores (p=0.068; p=0.081).