This is a question that seems to come up continually, and from what I hear, the Myki Call Centre aren’t covering themselves in glory in trying to explain it:
Why does Myki online topup take 24 hours or more? Why isn’t it instant like other services?
It doesn’t necessarily take that long. They say that to cover themselves. I’ve seen it work within an hour or two.
It takes a little while because unlike, say, mobile phone prepaid accounts or bank accounts or Citylink transponder accounts, the balance is maintained on the card itself.
When you top-up online, the transaction gets sent from the central computers (eg the web site) to every Myki reader and machine in the state (which may take some time, especially for tram and bus readers) to await the presence of your card.
Once your card is presented (as long as it’s within 90 days), the new balance is updated onto the card, and you’re set to go.
Note any top-up where the card is present on the system (eg vending machine or retailer) is instant.
As far as I know, all public transport smartcard systems work like this — the balance is always held on the card, for (theoretically) fast and reliable response times when touching on/off, especially for mobile readers eg on trams and buses.
It should be consistently faster, but it’ll never be instant.
- Don’t forget I’ve got a pristine Metcard on sale for charity! Bidding finishes this Thursday.
- PS. As Dave says in the comments, Auto Topup works differently to the above, and is instant once it’s set up and running (because after that each transaction is initiated from the card and reader).
Earlier today, @mykimate on Twitter posted this picture which helps explain the process:
Update: Since 2016, Myki top-ups have been sped-up, and are now done within about 90 minutes.