The first mention of time travel that I’ve found for Disney characters in the comics was the story of Uncle Wombat’s Tock Tock Time Machine which ran in Mickey’s daily strip from 22 Oct 1951 through 19 Jan 1952. As for comic books, the first one that I ever read in the comic books was when Mickey and Goofy traveled back to Blackbeard in August, 1968. I’ve since found travel in the comic books as early as 1964 (Gyro Gearloose travels in Uncle Scrooge 50) and 1962 (Chip ’n’ Dale 30). I’ll keep looking and add any new finds to my time-travel comic book page.
A fantastic time machine enables Mickey and Goofy to live in different periods of history. Right now they are aboard Mickey’s unarmed merchant vessel off the Carolinas in the early 1700’s—and off to starboard is a treacherous pirate ship. . .

Variants

(1)
  1. “Walt Disney’s Comics,” |pending byline|, in Mickey Mouse daily strips, 22 October 1951.