Introduction: To help prevent future morbidity and mortality, this study examined Australian Antarctic expeditioners’ first aid credentials and self-efficacy in providing emergency first aid in extreme environments. Methods: A mixed method survey assessed Australian personnel working on Antarctic stations. Volunteer participants (n = 83) provided data on first aid training, self-confidence of first aid readiness, and first aid preparations. The Extreme Conditions First Aid Confidence Scale (EC-FACS) was developed and validated for this study. Multivariate analyses tested associations between first aid background, demographics and EC-FACS. Open-ended comments were subjected to thematic analysis. Results: Over one-third of participants did not hold current first aid certificates at expedition commencement. Factor analysis demonstrated the EC-FACS was unidimensional, and internal consistency was high (α = 0.94), and showed first aid self-efficacy was moderately high, but participants’ confidence decreased as first aid scenarios became more complex. Experience providing emergency first aid and level of first aid qualification were the strongest predictors of overall first aid self-efficacy. Thematic analysis revealed expeditioners support higher first aid qualifications and want Antarctic-specific wilderness first aid training. Conclusions: These findings revealed that many Antarctic expeditioners may not be adequately prepared for first aid emergencies and have low confidence in handling complex medical situations. Based on these findings, we recommend higher first aid qualifications and training tailored to the Antarctic context. These modest steps can help prevent unnecessary and costly morbidity and mortality for extreme-condition expeditioners.