Auckland Transport have sold their millionth AT HOP card.
AT HOP is a smart card which can be used for bus, rail and ferry travel throughout Auckland.
AT HOP group manager, Denise Verrall, said surveys indicated 42 per cent of Auckland adults had a card as of June.
It was a "great improvement" on the same time last year, when 33 per cent of those surveyed said they had a card.
The card was rolled out on trains in late 2012 and then extended to ferry and bus services.
Four out of five customers now choose to pay for their public transport trip with the card, Verrall said.
"The card gives a discount of at least 20 per cent off single trip cash fares, excluding SkyBus and Waiheke ferry services. When you tag-on with your AT HOP card it is read in a 300th of a milli-second.
"Paying with an AT HOP card allows customers to pay just once for a single journey, that can involve up to five bus or train trips over four hours, with a maximum transfer time of 30 minutes between each trip."
Verrall said the uptake of the card has been very strong in Auckland.
"In 2013, Oyster, the London travel smartcard, was used in over 85 per cent of trips versus cash tickets, after 10 years in the market. In comparison, HOP has now reached 85.5 per cent after four years in the market, so we are very pleased with the uptake of HOP by Aucklanders."