The arrival of delayed flights was the cause of the long queues and lengthy waits for incoming passengers at Suvarnabhumi airport early Monday morning, according to the Immigration Bureau.
Pol Maj Gen Choengron Rimpadee, chief of Immigration Division 2, said the influx occurred between midnight and 2am on Monday, when 5,563 passengers arrived on 22 flights.
"Inbound traffic surged 33% above normal because of some delayed flights and the number of inbound passengers rose by about 1,000 above the usual number," Pol Maj Gen Choengron said.
Inbound passengers queue overflowed the immigration hall at Suvarnabhumi airport. Passengers took about 40 minutes to pass through immigration, even though immigration booths were staffed to the maximum, he said.
Arriving flights normally peaked between 1pm and 8pm, he said.
He also advised travellers to ensure they kept their boarding passes handy to speed up the process, because immigration officers needed to register the documents.