The calculated distance (air line) between San Andrés Itzapa and Retalhuleu is approximately 56 miles respectively 90 kilometers.
By car or train, the actual journey to Retalhuleu is certainly longer, as only the direct route (as the crow flies) between San Andrés Itzapa and Retalhuleu has been calculated here.
Air line (approximately)
90 kilometers
49 nautical miles