Objectives: We aimed to compare the observed rates of postoperative urethral stricture between patients undergoing thulium fibre laser enucleation of the prostate (ThuFLEP) using a 22 Fr miniaturised instrument strategy and those treated using a standard 26 Fr strategy. Methods: This prospective, two-centre comparative cohort study included 208 patients with benign prostatic hyperplasia and a prostate volume of less than 150 mL who underwent thulium fibre laser enucleation of the prostate (ThuFLEP) between 2024 and 2026. Patients were grouped according to the resectoscope sheath used at each centre: Group 1 comprised 99 patients treated with a 22 Fr miniaturised sheath and Group 2 comprised 109 patients treated with a standard 26 Fr sheath. The primary endpoint was the development of postoperative urethral stricture. Patient demographics and preoperative and postoperative clinical outcomes were also recorded. Results: Demographic and operative parameters were comparable between the groups. No significant difference was observed in mean prostate volumes (68.8 ± 34.1 vs. 70.8 ± 25.7 mL). Although the enucleation efficiency (g/min) was numerically higher in Group 1, the difference did not reach statistical significance (2.2 ± 1.1 vs. 1.8 ± 0.6; p = 0.082). Postoperative urethral stricture was observed in 2 patients (2.0%) in Group 1 and in 10 patients (9.2%) in Group 2. The incidence of stricture was significantly higher in Group 2 (p = 0.036). Conclusions: The 22 Fr ThuFLEP strategy was associated with a lower observed urethral stricture rate. However, the independent effect of sheath diameter could not be separated from centre- and surgeon-related factors. Further randomised studies are required to confirm these findings.