As all passenger traffic out of the airport is international in nature, the three major terminals in operation are equipped with immigration-processing facilities for international travel.
After recovering from a drop in passenger traffic as a result of the September 11 attacks in 2001, the severe acute respiratory syndrome (SARS) epidemic in 2003, the airport saw rapid growth in traffic which hit the 30-million mark for the first time a year later in 2004. In March 2008 and prior to the full effect of the financial crisis of 2007–2010 on the global economy, the airport predicted that it will handle 50 million passengers by 2012, with increases due to the opening of casinos in Singapore, together with the phased liberalisation of the Asean aviation sector. As predicted, the airport surpassed the 50-million mark for the first time in history in 2012