We expected oxygen saturation (SpO2) in children in coastal Papua New Guinea (PNG) to be higher than in PNG highlands children. Therefore, SpO2 was documented to determine the reference values of SpO2 in neonates and young children; 149 healthy neonates and 100 healthy infants and children < 5 years old were studied in Port Moresby. SpO2 ranged from 93% to 100% in both groups. The median SpO2 in neonates was 97% (CI 96.9-97.4) and in young children 98% (CI 97.5-98.0). We recommend 93% as the cutoff for administering oxygen to children under 5 years old in coastal PNG.