IndiGo and the Air India Group will progressively shift flights from Mumbai's Chhatrapati Shivaji Maharaj International Airport (CSMIA) to the newly built Navi Mumbai International Airport (NMIA) from December, in a phased transition that will reshape air travel for the Mumbai Metropolitan Region and clear capacity for the long-awaited redevelopment of CSMIA's Terminal 1.
The coordinated move, planned in phases through the 2027 summer aviation season, will transfer selected domestic and international services to the new airport while allowing airlines to retain their historical operating slots at the older airport.
The transition follows nearly 18 months of consultations between airlines and Adani Airport Holdings Ltd (AAHL), which operates both Mumbai airports. It is intended to ease congestion at CSMIA, accommodate rising air traffic and support the development of a dual-airport system for India's financial capital, a model already familiar in cities such as London, New York and Tokyo, where two or more airports share a metropolitan market.
For Mumbai, whose existing airport has long operated close to capacity, the opening of a second airport is one of the most significant aviation developments in years.
IndiGo, India's largest airline by market share, will progressively transfer 12 daily international departures from CSMIA to NMIA, covering its existing services to Bahrain, Riyadh, Dammam, Jeddah, Madinah, Kuwait, Ras Al Khaimah, Fujairah, Muscat, Dhaka and Jakarta.
The airline will also introduce a daily service to Kathmandu, taking its international network at NMIA to 12 destinations between February and July 2027, according to a joint statement issued by IndiGo and the airport operator. IndiGo will also shift a portion of its domestic operations to NMIA to support its international services and facilitate onward connections for passengers.
The Air India Group, meanwhile, will progressively shift Air India Express services to Jeddah, Riyadh, Dammam, Doha, Muscat and Sharjah to NMIA, with the transition expected to be completed by the International Air Transport Association's Northern Summer 2027 season. Air India Express will operate four daily domestic flights from NMIA from December 2026, and it plans to launch services to Kuwait and operate existing services to Oman from January 2027.
The group said the move was part of the wider airport transition programme for domestic and international airlines and would support the redevelopment of CSMIA's Terminal 1.
That redevelopment is a central reason for the shift. CSMIA's Terminal 1, which handles domestic traffic, is due to be rebuilt, and the work is expected to raise its annual passenger-handling capacity by about 33 per cent, from 15 million to 20 million. Such a project cannot be carried out at full scale while the terminal continues to operate at its current intensity, so moving a share of flights to Navi Mumbai creates the breathing room needed for construction.
The airlines' retention of their historical slots at CSMIA means they are not surrendering their position at the older airport; they are, in effect, expanding across two airports while the older one is rebuilt.
For passengers, the transition will require attention to detail. Mumbai's two airports are in different parts of the metropolitan region, and a passenger who arrives at one airport and departs from the other, or who is connecting between flights, will need to allow for the transfer.
Airlines and the airport operator will need to communicate clearly about which flights operate from which airport, particularly during the phased period when services are moving gradually rather than all at once. Booking platforms, check-in information and signage will all matter, and the experience of the first months will shape public confidence in the dual-airport system.
The move also reflects the growing importance of the Gulf and West Asia routes for Indian aviation. Many of the destinations being shifted, including Riyadh, Jeddah, Dammam, Doha, Muscat, Kuwait and Sharjah, are among the busiest international routes from Mumbai, driven by business travel, tourism and the large Indian diaspora in the Gulf. Dhaka, Kathmandu and Jakarta add a South and Southeast Asian dimension to the new airport's network.
By concentrating a set of international services at NMIA, the airlines can build connecting traffic there, feeding passengers from domestic flights onto international departures.
Not everyone in the industry has welcomed the reallocation. Reports have noted that a proposed reallocation of air traffic ahead of the Terminal 1 redevelopment has faced opposition from other airlines, and the phased nature of the IndiGo and Air India moves reflects the delicate negotiations involved.
Airlines have different networks, fleet plans and commercial interests, and a shift of flights between airports affects ground handling, crew rostering, maintenance and partnerships. The fact that IndiGo and Air India Group, the two largest players, have agreed to move is significant, but the broader transition programme will continue to involve other carriers.
For AAHL, the transition is also an opportunity to establish NMIA as a functioning second hub rather than a secondary facility. The operator has been working with IndiGo to put the required infrastructure in place, and the airline has linked the move to its wider expansion plans, including the induction of A320 and A321 aircraft and A321XLRs in 2027.
Those longer-range narrow-body aircraft will allow the airline to expand its international network across Asia, Africa and Europe without adding to capacity constraints at CSMIA, and NMIA gives it room to grow.
The wider context is Mumbai's growth. The metropolitan region continues to expand, with new residential and commercial development in Navi Mumbai and its surroundings, and the new airport is intended to serve that growth as well as the older city. A dual-airport system, if it works well, can spread traffic, reduce congestion and give passengers more choice.
If it works poorly, with confusing transfers and weak transport links, it can frustrate travellers. Much will depend on surface connectivity, including road and rail links between the two airports and the city, and on how smoothly airlines handle the transition period.
The phased timeline gives all parties time to adjust. Starting in December 2026 and continuing through the 2027 summer season, the shift is gradual rather than abrupt. Passengers booked on affected routes should check their departure airport carefully, especially for travel in the first months of the transition, and airlines are expected to notify customers of changes.
For Mumbai's aviation market, the coming year will be a test of whether two airports can serve one city effectively, and the IndiGo and Air India moves are the first major step in finding out.
(Reporting based on The Indian Express and Business Standard.)