From Rockstar Games:
Digital pre-loading on PlayStation 5 will begin on Tuesday, November 10 at midnight local time in your respective time zone. On XBOX Series X|S, pre-loading begins globally on Tuesday, November 10 at 12 a.m. GMT. Code-in-box versions for both consoles should be available from retailers beginning November 12.
The pre-load file will require up to 212 GB depending on your device, so make sure you've got ample space to begin pre-loading as soon as possible.
For details on how to pre-load Grand Theft Auto VI for PlayStation 5 and XBOX Series X|S, please visit the Rockstar Support site.
On November 19 we will be adding an official printable Grand Theft Auto VI cover art poster and map of Leonida as a free digital download to the official site. A double-sided physical version of this poster will also be made available shortly after launch from the Rockstar Store — for $0.99 on its own or as a free gift with any purchase from the Rockstar Store.
