While I cannot provide direct links, the Japanese dub of Big Hero 6 is likely available on:
The film was well-received in Japan, praised for its homage to Japanese robotics and technology (e.g., Baymax as a sentÅin [cleaner robot] character). It also sparked renewed interest in the Big Hero 6 manga by Go Nagai (1976), which inspired the story. big hero 6 japanese dub link
For collectors, the official Japanese home release includes the Japanese dub in pristine 5.1 surround sound. You can purchase these from retailers like CDJapan or Amazon Japan. The "link" here is a physical purchase link, but once you own the disc, you have the definitive version of the dub. While I cannot provide direct links, the Japanese