Background/Objectives: Rock climbing is a multifaceted athletic activity that requires both psychological and physiological resilience. This study aimed to examine the differences in psychological factors and fatigue predictors between novice and advanced climbers, with a focus on the interplay between experience and performance. Methods: The study included 60 participants categorized based on climbing experience (novice or advanced). Psychological and physiological assessments were conducted, including heart rate variability (HRV), grip strength, rate of force development (RFD), subjective perceived stress (SPS), and anxiety levels using validated questionnaires. Results: Advanced climbers exhibited lower anxiety levels and better sympathetic modulation compared to novices. Significant differences in HRV parameters, grip strength, and RFD were observed, reflecting the impact of experience on physiological responses. Advanced climbers demonstrated notable strength decreases post-climbing, supporting the utility of a force sensor on a 20 mm edge for assessing forearm fatigue. Correlations between cortisol levels, anxiety, and self-confidence during climbing were also identified. Conclusions: The findings highlight the importance of psychological and physiological factors in climbing performance. Forearm fatigue emerged as a critical predictor, suggesting that portable force sensors can optimize training and injury prevention. Insights from this study may enhance training protocols and improve real-time performance monitoring in climbers.