This randomized controlled trial investigated the acute effects of floss band (FB) application at different pressures on multidimensional ankle stability in patients with chronic ankle instability (CAI). Forty-two male participants with CAI were randomly assigned to a medium-pressure (MP, 150 mmHg), high-pressure (HP, 200 mmHg), or control group (CG, non-compressive bandage). Outcomes included the Y-Balance Test (YBT), single-leg landing stability (assessed via surface electromyography), ankle proprioception, and static balance, measured at baseline (T0), 5 min (T1), 25 min (T2), and 45 min (T3) post-intervention. The results showed that both MP and HP groups exhibited significant improvements in YBT composite scores, lower limb muscle activation during landing, and joint position sense accuracy at T1 and T2 compared to T0 (all p < 0.05), with the MP group demonstrating longer-lasting benefits up to T3. The MP group also significantly outperformed the CG across multiple dynamic stability and neuromuscular metrics at early time points (p < 0.05). Improvements in static balance were limited and transient. These findings indicate that a single application of FB, particularly at 150 mmHg, can acutely enhance dynamic stability, neuromuscular control, and proprioception in CAI patients, with effects sustained for up to 45 minutes, supporting its use as an effective pre-activity or pre-rehabilitation intervention.