The country star had been scheduled to perform at the venue as part of his much-anticipated comeback to music from 25-29 July.
However Dublin City Council refused permission for two of the gigs, prompting the star to say it was "five gigs or none at all" as it "would be like asking to choose one child over another".
After weeks of uncertainty and proposed compromise bids, it was confirmed this week that all five gigs are definitely cancelled.
The process has now begun to refund 400,000 tickets.
The Ticketmaster refund information is as follows:
For Ticketmaster tickets purchased over the Phone, Online or Mobile
No action is required if you (the ticket purchaser) purchased tickets by these channels. On Tuesday, 15th July a full refund including service charges will automatically be returned to the card used to make the purchase. Please allow 7-10 working days for the refund to reach your account.
For tickets purchased through Ticketmaster ticket centres
POSTAL: A refund form is available via the Garth Brooks FAQ page at www.ticketmaster.ie/gbrefunds. Please print, complete and return this form along WITH your GARTH BROOKS TICKETS to PO Box 4695, Dublin 2. Please make a note of the show date and your seat details and retain the left hand portion of the refund form for your records. A full refund including service charges will be processed by bank transfer within 21 days of receiving the form and tickets.
IN PERSON AT TICKET CENTRES: From July 15th you may return your tickets to the ticket centre where you purchased them from and complete the refund form which will be available at the ticket centre from this date. The completed form together with your GARTH BROOKS TICKETS should be handed in at the ticket centre. Please make a note of the show date and your seat details and retain the left hand portion of the refund form for your records. A refund by bank transfer will be processed within 21 days of receiving the form and tickets.
Please note: If you purchased tickets from News & Deli Dundalk /Fassaugh Stores Cabra, Dublin /Whites Wexford /the Irish Shop Ennis/ Cusack Park Ennis, these are no longer affiliated with Ticketmaster. Refunds for tickets purchased at these ticket centres are available from any existing Ticketmaster ticket centre using the same refund process as above or alternatively you can use the postal option also set out above.
See www.ticketmaster.ie/gbrefunds for full details.