Yes, I'm aware of the "train". But it's ridiculous! It will take you to Robina station and a chauffeur has to take you to the airport and the service is only available one way due to license restriction!
Brisbane's Airtrain - Gold Coast Airport
So on your return flight from NRT-OOL, if you have no one to pick you up, or if you arrive on the day where there is no shuttle service (eg. Mon), what are you gonna do? Taxi will be the only way, or some other private airport pick up service which costs $100 oneway.
What kind of public transport is that if it only provides one way service? Imagine if Tokyo to NRT is only one way, no one will fly to NRT.
Thats the airtrain service, not the public service which is a train and bus transfer. I have take it a number of times, it's cheap and easy but time consuming, and obviously both ways.
go card adult fare: $16.28
2 hrs 1 min | total walk 102m | 1 transfer
9.59am - 11.22am
Catch train BDVL Airport via Brisbane to Varsity Lakes - Gold Coast to Varsity Lakes station, platform 2, Varsity Lakes
Minor disruptions More info & times
11.22am - 11.24am
Walk 102m to Varsity Lakes station, Varsity Lakes
11.29am - 12.00pm
Catch bus 760 Robina Town Centre, Varsity Lakes, The Pines, Airport, Tweed to Gold Coast Airport, Bilinga
This is a 18 zone journey, travelling in zones 1 - 18.
Fare information for the travel option currently displayed.
Ticket type Price
go card adult $16.28
$13.02 (off-peak)
go card concession $8.14
$6.51 (off-peak)
Single paper adult $23.60
Single paper concession $11.80
A taxi service may be available for your journey.