Check your local library for the Blu-ray or DVD of Train to Busan . Most library systems carry popular foreign films. The physical disc almost always contains the English dub audio track. This is the only pure "free" method that is 100% legal and safe.
The film was produced by Next Entertainment World and RedPeter Film in South Korea. Unlike major Hollywood blockbusters or even big-budget anime films, most Korean live-action films are not dubbed into English for international release. The justification is simple: the budget for dubbing (hiring voice actors, syncing audio, mixing tracks) is expensive, and studios assume that the core audience for foreign cinema prefers subtitles to preserve the original actors' performances. train to busan english dub free
Here’s the honest situation: