Unlike most Indian metro systems still promising an airport line "soon," Mumbai's is already running - and it's a genuine reason to skip the cab.
Line 3 (Aqua Line) goes straight to both terminals
Mumbai's first fully underground metro line has been fully operational since 8 October 2025, running 33.5 km across 27 stations from Cuffe Parade to Aarey JVLR - and it serves both CSMIA Terminal 1 and Terminal 2 directly. Terminal 2 connects via a purpose-built roughly 100-metre foot overbridge from the CSMIA T2 metro station straight into the terminal.
What it costs and how long it takes
A full-length journey - say, from the Cuffe Parade area to the airport, around 30 km - runs about ₹50. A CSMT-to-Terminal 2 run takes roughly 35-40 minutes, which beats fighting airport-road traffic most times of day.
One thing to get right: Line 7 does NOT go to the airport
If you're looking at the network map and see Line 7 (Red Line) running north-south nearby, don't assume it connects to the domestic terminal - a planned extension there was dropped back in 2018 due to technical challenges. The Aqua Line's own airport stations are your only direct metro route in.
Bottom line
If you're flying out of CSMIA and you're anywhere near a Line 3 station, take the metro - it's fast, it's cheap, and unlike the airport-line promises in most other Indian cities, this one is real and running today.