Officials said the incident was reported from the terminal-III area of the airport in the wee hours when the three reached the airport to take their flight.
"The passengers were intercepted after their activities were found suspicious. They were found concealing Euro 3,50,000 in their headgear and rectum," the officials said.
The three were offloaded and handed over to customs authorities for further probe, they said, adding the seized currency is worth over Rs 2.6 crore.