Background Reiki is a biofield therapy which is based on the explanatory model that the fields of energy and information of living systems can be influenced to promote relaxation and stimulate a healing response. Objective To conduct a pragmatic within-subject pilot trial of a remote Reiki program for frontline healthcare workers’ health-related symptoms during the COVID-19 pandemic. Methods Healthcare professionals in the UK (eg, physicians, nurses, and paramedics) were eligible to sign up for a distance Reiki program and were also invited to participate in the research study. Eight Reiki practitioners simultaneously gave each participant Reiki remotely for 20 minutes on 4 consecutive days. Feasibility of the research was assessed, including recruitment, data completeness, acceptability and intervention fidelity, and preliminary evaluation of changes in outcome measures. Participants’ stress, anxiety, pain, wellbeing, and sleep quality were evaluated with 7-point numerical rating scales. Measures were completed when signing up to receive Reiki (pre) and following the final Reiki session (post). Pre and post data were analyzed using Wilcoxon signed ranks tests. Results Seventy-nine healthcare professionals signed up to receive Reiki and took the baseline measures. Of those, 40 completed post-measures after the 4-day intervention and were therefore included in the pre-post analysis. Most participants were female (97.5%), and the mean age was 43.9 years old (standard deviations = 11.2). The study was feasible to conduct, with satisfactory recruitment, data completeness, acceptability, and fidelity. Wilcoxon signed ranks tests revealed statistically significant decreases in stress (M = −2.33; P < .001), anxiety (M = −2.79; P < .001) and pain (M = −.79; P < .001), and significant increases in wellbeing (M = −1.79; P < .001) and sleep quality (M = −1.33; P = .019). Conclusions The Reiki program was feasible and was associated with decreased stress, anxiety and pain, and increased wellbeing and sleep quality in frontline healthcare workers impacted by the COVID-19 pandemic.