Under a deal sealed on Friday, Incheon airport – which serves the Seoul area and which is one of the most modern in the world – will share its experience in constructing a large transport hub.
Poland is planning to build its new airport between the capital, Warsaw, and the central city of Łódź. The high-profile project aims to integrate air, rail and road transport.
Polish Prime Minister Mateusz Morawiecki said during a ceremony on Friday: "Starting today, one of the largest projects in the history of Poland has an exceptional strategic partner."
He added: "We are opening a completely new chapter in the history of Polish modernization."
The first passengers will be able to use the new airport towards the end of 2027, public broadcaster Polish Radio's IAR news agency reported.
The new Solidarność (Solidarity) Airport will be able to handle up to 45 million passengers a year in the first stage of the project, according to Polish state news agency PAP.
President Andrzej Duda said last year that a host of big-ticket projects undertaken by Poland's government were helping steer the country through the global coronavirus crisis.