At the Magic Kingdom, Stitch greets fans on Main Street USA.
In Tokyo Stitch usually meets in Arabian Coast, which we find quite odd, or in Tomorrowland with Angel.
At Disneyland Paris he can sometimes be found in Discoveryland near Star Tours.
In California, Stitch seems to be quite rare these days, though if you pay for the meal, you can usually (but not always) get him at the Surf's Up breakfast at the Paradise Pier Hotel.
In Hong Kong, Stitch used to meet in Tomorrowland, but seems less frequent now.
Select Disney Cruise Line sailings sometimes feature Stitch. You should check your Personal Navigator for details.