Background <p>The laryngeal mask airway (LMA) is essential in anesthesia, using an air-inflatable cuff for optimal pharyngeal fit. The i-gel^® LMA (i-gel) is unique for its thermoplastic elastomer material making an air-inflatable cuff unnecessary and has shown higher oropharyngeal leak pressure (OLP) than first-generation LMA (cLMA) in neutral head position, however, mixed results for head rotation. This prospective study aimed to compare OLP between the cLMA and i-gel during head rotation.</p> Methods <p>Patients undergoing elective surgery securing the airway with either cLMA or i-gel were included. Exclusion criteria included a Body Mass Index &gt; 30&#xa0;kg/m², cervical spine pathologies or restricted head rotation. OLP was measured after induction at 60° bilateral head rotation for primary outcome. Secondary outcomes were OLP at 0° head rotation and postoperative complications on postoperative day 1.</p> Results <p>116 patients were randomized to either the cLMA (<i>n</i> = 60) or i-gel (<i>n</i> = 56) group. No significant difference was found in the OLP with 60° head rotation to the left (cLMA 20 cmH₂O [Interquartile range [IQR] 18–22], i-gel 21 cmH₂O [IQR 18-22.75], <i>P</i> = 0.752) and the right (cLMA 20 cmH₂O [IQR 18–22], i-gel 20 cmH₂O [IQR 15–21], <i>P</i> = 0.324). OLP was also comparable in a neutral head position (<i>P</i> = 0.368). No significant differences in postoperative outcome were observed.</p> Conclusions <p>This study demonstrated comparable OLP between cLMA and i-gel during head rotation. This indicates equivalent efficacy and seal integrity of both LMAs during head rotation, resulting in sufficient tidal volumes during rotated head positions.</p> Trial registration <p>German Clinical Trials Register, retrospectively registered under DRKS00031785 (date of registration 26.04.2023).</p>