Peroral endoscopic myotomy (POEM) is the preferred treatment for type III achalasia, as it allows the myotomy of both the lower esophageal sphincter (LES) and the spastic esophageal segment [1]. However, the optimal myotomy length varies among patients [2]. The Endoluminal Functional Lumen Imaging Probe (EndoFLIP) provides assessment of LES distensibility and is increasingly used to tailor myotomy length, especially during re-interventions [3]. We report the case of a 29-year-old man with type III achalasia initially treated with posterior POEM. After early improvement, he developed recurrent dysphagia. During an anterior re-POEM, EndoFLIP identified two areas of reduced distensibility, guiding targeted extension of the myotomy. Final measurements confirmed normalization of distensibility. The patient was discharged two days later and remained asymptomatic at six-month follow-up.