FFXIV Producer Naoki Yoshida announced Data Center Travel will arrive through an upcoming 6.1x Patch. Additionally, he explained some of the limits that Data Center Travel will have. Specifically, he mentioned visiting players in Data Centers located, physically, within other regions. However, Yoshida does state that cross-region travel between Data Centers is possible. At this time the team is still currently considering implementation of that specific Data Center transfer feature.
That said, Yoshida briefly discussed how players will be able to travel between Data Centers. This included mention that Data Center travel will be initiated from the Character Selection screen. This means that users who wish to travel Data Centers will need to select the Data Center of their choosing before properly logging into a character.
Other stipulations to the system include the inability to currently join Free Companies or Linkshells on other Data Centers. Outside of that, however, there are no other restrictions to the feature. A definite date as to when this feature will arrive has yet to be revealed.
Final Fantasy XIV is available for PlayStation 4, PlayStation 5, and PC.