Introduction: This cross-sectional study aimed at evaluating impacts of healthcare simulation training, either in-situ or lab-based, on personal strengths of healthcare workers (HCWs) and organizational outcomes during the COVID-19 pandemic. Methods: COVID-19 Taskforce was established to formulate standardized scenario-based simulation training materials in late-January 2020. Post-training questionnaires made up of 5-point Likert scales were distributed to all participants to evaluate their personal strengths, in terms of i) assertiveness, ii) mental preparedness, iii) self-efficacy, iv) internal locus of control, and v) internal locus of responsibility. Independent sample t-tests were used to analyze between-group difference in "In-situ" and "Lab-based" group; and one-sample t-tests were used to compare change in personal strengths with reference point of 3 (Neutral). Kirkpatrick's Model served as the analytical framework for overall training effects. Results: Between 05 February and 18 March 2020, 101 sessions of simulation training were conducted in "In-Situ" at either Accident & Emergency Department (20, 20%) or Intensive Care Unit (15, 14%) and "Lab-based" for Isolation (30, 30%) and General Wards (36, 36%). 1,415 hospital staff members, including 1,167 nurses (82%), 163 doctors (12%) and 85 patient care assistants (6%), were trained. All domains of personal strengths were scored 4.24 or above and statistically significantly increased when comparing with reference population (p < .001). However, no significant differences between in-situ and lab-based simulation were found (p > .05), for all domains of personal strengths. Conclusion: Healthcare simulation training enhanced healthcare workers' personal strengths critical to operational and clinical outcomes during the COVID-19 pandemic.