Stuttering is a challenging condition characterized by disfluencies which prior work has found to be momentarily improved during whispering. The present study explores the clinical potential of whispering by examining whether the benefits of whispering remain stable with short-term use, extend to conversation tasks, and are feasible in daily life. Sixteen adult persons who stutter completed tests assessing the amount of stuttering for normal voiced speech and whispering during both conversation and reading-aloud tasks. Participants then used whispered communication in their daily lives and reported their subjective experiences. After three weeks, effectiveness tests were repeated. Stuttering severity was significantly lower for whispered speech (vs. typical speech) during a conversation task (50% reduction), although this effect was smaller than for the reading-aloud task (85% reduction). This reduction remained present and comparable in magnitude after three weeks of approximately 5 to 10 minutes of daily whispering. Participants subjectively indicated positive experiences with respect to the effects of whispering on fluency and reported that whispering helped reduce stuttering-related anxiety. However, four participants (25%) reported negative voice side effects (e.g., hoarseness, vocal-fold strain), associated with regular whispering. Occasional use of whispering can effectively reduce stuttering and related behaviors during both reading-aloud and conversational speech. This result paves the way for future technological applications that convert whispered speech into natural sounding speech in real-time.