Impaired upper airway dimension in adults with Isolated Robin Sequence (IRS) can alter airflow dynamics, increasing the risk of pharyngeal collapse and the onset of obstructive sleep apnea. This study aimed to characterize the upper airways of six young adults (20.83 ± 6.40 years) with IRS, using computational fluid dynamics. Upper airways of six patients were reconstructed using 3D segmentation, generating unstructured hybrid meshes with ≥4 million tetrahedral elements. Flow simulations at 15 l/min were solved using the realizable k-ε model and the finite volume method. Morphophysiological variables assessed were: total airway volumes, minimal cross-sectional areas, average pressure, velocity magnitude, wall shear stress, turbulent kinetic energy (k) production, and resistance. Airway volume corresponded to 29.32 ± 4.65 cm³ and minimal cross-sectional area was 1.00 ± 0.55 cm