Kochi Metro is considering an underground transit hub as part of Phase Three to connect Cochin International Airport, a proposed new railway station at Nedumbassery and the metro network through an integrated tunnel system, according to a report by Manorama. The concept is being examined in the Detailed Project Report for the Aluva–Angamaly corridor and is presented as an option to provide seamless intermodal transfers within the airport precinct and adjacent transport nodes.

Initial discussions had envisaged a three km subterranean stretch, but sources now indicate that nearly eight km of underground alignment are being examined, which would represent the first significant underground section in Kerala given that Phase One and Phase Two of Kochi Metro contain no underground alignments. The plan centres on an underground metro station near the Taj Cochin International Airport Hotel that would act as the principal interchange and enable vertical and horizontal movements between modes within a single complex.

Planners anticipate that the integrated underground hub would allow passengers to move directly between the airport terminal, metro platforms and long distance rail services without entering surface traffic, thereby reducing transfer times and improving the quality of connectivity. Realising the scheme is likely to require sophisticated tunnelling techniques, carefully designed station cavities, comprehensive ventilation and fire safety systems, and detailed planning for passenger circulation, luggage handling and accessibility.

The Detailed Project Report remains under consideration and does not yet define a construction timeline or final cost estimates, and stakeholders are expected to require further technical studies, environmental clearances and coordination with aviation and railway authorities. If approved, the proposal would substantially expand the reach of Kochi Metro and introduce underground construction practices to the state, with implications for future corridor design and urban transport integration.