 Travellers from KL Sentral to KLIA and klia2 can purchase the tickets to board the KLIA Ekspres at the KL City Air Terminal (KL CAT) which is an integral part of the KL Sentral transport hub while travellers from KLIA and klia2 to KL Sentral must purchase their tickets before boarding in order to pass through the automated barriers at KL Sentral.Ticketing is done either by automated ticketing machines or by ticketing staff at the stations.A one-way trip costs RM55 (increased from RM35 on 1 January 2016) from KL Sentral to KLIA/klia2 and vice versa.