The African dwarf crocodiles, an endangered species banned from international trade, were en route from Nigeria to Korea. They grow to 1.5 metres (5ft). It is believed they were destined for the pet trade in Korea.
They are being held at the airport's animal reception centre and may be sent to a breeding programme.
Some 95 other reptiles and amphibians, including 12 royal pythons and 13 monitor lizards, were also confiscated.
Forged documents with the reptiles, which were packed individually in sacks, claimed the shipment consisted of six American alligators and four Nile crocodiles ranched in Benin, west Africa.
A spokesman for Customs and Excise, Nigel Knott, said: "It is believed that the two shipments originated from Nigeria and knowing that they would not get permits from there, the exporters tried to disguise their true origin by forging the Benin export permits."
The traders probably believed the crocodiles would not be discovered because of the dangers of examining dangerous animals, he said.
"Examination and identification of large crocodiles is not without its difficulties, not least from a health and safety angle."
