This weeks Famitsu did an extensive feature on Final Fantasy X in honor of its 20th anniversary that included an interview with Tetsuya Nomura, Final Fantasy character designer, Kazushige Nojima, scenario writer, event director, Motomu Toriyama, plus more.
Among the various things asked was the possibility of Final Fantasy X-3 being made. This makes sense, as Final Fantasy X is the first title in the franchise to have a traditional sequel, after which it became somewhat common, not to mention the story continued in Final Fantasy X: Will, the audio drama, and of course the novel Final Fantasy X-2.5 that continues things further.
In response to this, Nomura confirmed that Nojima had basically created an outline of what a potential Final Fantasy X-3 would look like, going on to say that the aforementioned continuations were based off the ideas present in said outline.
Before anyone gets too excited, Nomura mentioned that while it’s possible, it will be after Final Fantasy VII Remake is completed.