The primary purpose of this study was to investigate the reliability of the isometric push-up (IPU), dynamic push-up (DPU), and force plate pop-up (FP POP) as measures of upper-body isometric and dynamic strength qualities in surfing athletes. Furthermore, the study aimed to compare pop-up performance between stronger and weaker surfers. Eighteen female (n=9) and male (n=9) surfers (age=28.1±6.4 yrs, mass=69.6±10.4 kg, height=172.5±6.7 cm) completed a battery of upper-body strength assessments, of which exhibited high between-day reliability: (IPU, (CV%=4.7, ICC=0.96), DPU (CV%=5.0, ICC=0.90), FP POP (CV%=4.4, ICC=0.90). Participants were subsequently split into stronger (n=9) and weaker (n=9) surfers based on normalized peak force (PF) attained in the IPU. Pop-up performance was measured both in the water and during the FP POP, and was referred to as time to pop (TTP). Significant between group differences were observed for normalized PF during IPU (d=1.59, p<0.01) and DPU (d=0.94 p=0.04). Although not significant, there was a large magnitude difference in FP POP (d=0.80, p=0.08) and FP TTP (d=0.85, p=0.07). Significant correlations were identified between normalized IPU PF and normalized DPU FP (r=0.69, p=0.03) and FP TTP (r=0.73, p=0.02) in the stronger group. The weaker group exhibited a significant inverse correlation between normalized IPU PF and in water TTP (r=-0.77, p<0.01). The results suggest improvements in pop-up performance may be elicited by improving dynamic strength for stronger surfers, whereas pop-up performance in weaker surfers may be elicited by improving maximum strength. The upper-body strength assessments provided a novel insight into strength qualities that are associated with in water performance of surfers (TTP).