Background <p>Single-incision laparoscopic surgery (SILS) has been accepted in bariatric surgery due to its cosmetic advantages. However, transumbilical incisions in patients with severe abdominal fat accumulation and musculofascial weakness are associated with higher wound complications. This study introduced a novel transverse umbilical incision through umbilical categorization and anatomical analysis to optimize outcomes.</p> Methods <p>Patients who underwent transumbilical single-incision laparoscopic bariatric surgeries between January 2022 and March 2023 were enrolled. The umbilical types were categorized based on photographic analysis. The interrectus distance (IRD) and abdominal wall thickness were measured on abdominal CT. The operative characteristics, wound pain, and complications were recorded. The scar condition and patient satisfaction were evaluated.</p> Results <p>The cohort comprised 286 patients with a mean age of 36.0 ± 8.9 years (range 13–66 years) and mean body mass index of 38.9 ± 6.0&#xa0;kg/m² (range 28.7–60.3&#xa0;kg/m²). The mean IRD around the umbilicus was 3.24 ± 1.20&#xa0;cm (range 1.19–7.36&#xa0;cm). The transverse transumbilical incision was applicable to patients with horizontal (46.9%), T-shaped (23.8%) and oval umbilici (15.4%). Wound complications occurred in 1.7% of patients, including 2 superficial infections, 2 wound dehiscence, and 1 incisional hernia.</p> Conclusion <p>The transumbilical transverse incision method provides surgical safety and satisfactory cosmetic outcomes.</p> Graphical Abstract <p></p>