Pharyngeal lumen volume is prone to increase as a consequence of pharyngeal muscle atrophy in aging. Yet, the impact of this on swallowing mechanics and function is poorly understood. We examined the relationship between pharyngeal volume and pharyngeal swallowing mechanics and function in a sample of healthy community-dwelling seniors. Data were collected from 44 healthy seniors (21 male, mean age = 76.9, SD = 7.1). Each participant swallowed 9 boluses of barium (3 × 5 ml thin, 3 × 20 ml thin, 3 × 5 ml nectar). Pharyngeal shortening, pharyngeal constriction, pyriform sinus and vallecular residue were quantified from lateral view videofluorosopic swallowing studies. Pharyngeal lumen volume was captured during an oral breathing task with acoustic pharyngometry. In addition, within-participant measures of strength and anthropometrics were collected. Four linear mixed effects regression models were run to study the relationship between pharyngeal volume and pharyngeal constriction, pharyngeal shortening, pyriform sinus residue, and vallecular residue while controlling for bolus condition, age, sex, and posterior tongue strength. Increasing pharyngeal lumen volume was significantly related to worse constriction and vallecular residue. In general, larger and thicker boluses resulted in worse pharyngeal constriction and residue. Pharyngeal shortening was only significantly related to posterior tongue strength. Our work establishes the utility of acoustic pharyngometry to monitor pharyngeal lumen volume. Increasing pharyngeal lumen volume appears to impact both pharyngeal swallowing mechanics and function in a sample of healthy, functional seniors.