A phase II single-arm trial was conducted from June 2017 to October 2018 to evaluate the efficacy and safety of transcutaneous posterior tibial nerve stimulation (TPTNS) for premature ejaculation (PE) treatment. Twelve men with PE and no prior treatment were enrolled, one was withdrawn and 11 subjects provided data for the main outcome. TPTNS consisted of 30-min sessions of the application of 20 Hz with a pulse amplitude of 200 µsec. The intensity was adjusted based on individual sensibility. The participants received 3 weekly sessions for 12 consecutive weeks. Follow-up continued for 9 months after therapy completion. The main outcome was a threefold increase in the intravaginal ejaculation latency time (IELT) at week 12. Eleven patients completed therapy, and 54.5% (p = 0.037) showed tripled baseline IELT scores at week 12. The IELT increased 4.8-fold, 6.8-fold, and 5.4-fold at weeks 12, 24, and 48, respectively. One episode of constipation was reported, and one patient reported a sensation of heat in the leg during one therapy session. The findings suggest that TPTNS therapy delays ejaculation in patients with lifelong premature ejaculation, with no serious secondary effects. Controlled trials with larger sample sizes are needed to verify these results.