The detailed project report for Kochi Metro Phase three envisages a 17.5 km line from Aluva to Karayamparambu with a direct link to Kochi airport and provisions for airport check-in at select stations. The alignment will pass through Kariyad, Nayathode, Kavarapparambu and Arikkal Junction and will terminate at Karayamparambu in Angamaly, while excluding direct connectivity to Angamaly railway station. The DPR lists fifteen stations including Thottakkattukara, Kunnampuram, Parambayam, Nedumbassery, Athani and an Airport Railway Station.

Cochin International Airport Ltd has held discussions with Kochi Metro Rail Ltd on the preferred location for the airport metro station and officials have identified land in front of the Taj Hotel between the international and domestic terminals as most suitable. The proposal includes provision of an escalator linking the metro station with the airport and a connection to the airport railway station to facilitate transfers between air and rail networks. Around 20 cents of CIAL land is reported to be earmarked for the project.

The DPR proposes measures to increase train frequency during peak hours and to reduce headway to align with flight schedules to provide more convenient airport connectivity. Unlike Phase two, the report specifically incorporates parking facilities at proposed stations and considers an elevated viaduct as the most economical option for the corridor. An underground stretch near the airport is included only as a reference option and is not the preferred alignment. Officials said routing the line to serve Angamaly railway station would necessitate a return to NH 544, lengthen the corridor and require additional land acquisition.

The project is targeted for completion by 2031, with land acquisition and pending approvals expected to begin in 2027 and the whole process anticipated to take four years. The Phase three cost is currently estimated at around Rs 70-80 billion (Rs 70-80 bn) while an underground stretch could add nearly Rs 20 billion (Rs 20 bn) to the project cost. The DPR identifies the present alignment as the shortest route to the airport and proposes station amenities to improve passenger convenience.