One end of Greenpoint Avenue is served by the Greenpoint Avenue station on the "G" line; the other end is served by the 46th Street station on the #7 line. On weekdays, the B24 bus runs along Greenpoint Avenue, connecting one end to the other.
From JFK, take the AirTrain to Jamaica, and then take a Manhattan-bound "E" train to Roosevelt Avenue/Jackson Heights station for the transfer to the #7; or take the "E" to Court Square/23rd Street station for the transfer to the "G". If you use a Metrocard to enter the subway at Jamaica, you will automatically get a free transfer to the B24 bus, if needed.
One end of Greenpoint Avenue