Voice work
In addition to voicing the Ent Treebeard in Lord of the Rings, Rhys-Davies has lent his distinctive voice to many video games and animated television series, including the role of Hades in Justice League, the original voice of Man Ray in SpongeBob SquarePants (until both roles were recast with Bob Joles), and numerous times in Gargoyles (1994–1996), as the character Macbeth. He also lent his vocal talents to the games Freelancer (as Richard Winston Tobias) and Lords of Everquest (both in 2003) and the game Quest for Glory IV: Shadows of Darkness, which was released with his narration on a CD-ROM version in 1995. Rhys-Davies also had a voice role on Baldur's Gate: Dark Alliance as the character Jherek, and narrated a documentary called The Glory of Macedonia. Next Generation magazine gave its Dune 2000 review "an automatic one-star deduction for featuring John "Multimedia Whore" Rhys-Davies in the FMV."
Rhys-Davies' voice can be heard on the 2009 documentary Reclaiming the Blade. In the narration, he explores swords, historical European swordsmanship and fight choreography on film, a topic very familiar to Rhys-Davies from his experiences in The Lord of the Rings trilogy, where his character wielded an axe in many scenes.
In 2004, Rhys-Davies was the unknowing subject of an internet prank that spread false rumours in several mainstream media sources that he was scheduled to play the role of General Grievous in Star Wars Episode III.
Rhys-Davies is the narrator of The Truth & Life Dramatized audio New Testament Bible, a 22-hour, celebrity-voiced, fully dramatised audiobook version of the New Testament which uses the Revised Standard Version-Catholic Edition translation. In 2011, he presented KJB: The Book That Changed The World, which features Rhys-Davies reading diverse snippets from the King James Version.
Rhys-Davies' voice work also includes voice-over work with Breathe Bible. In 2016, he provided spoken words for Voices of Fire, the sixth album by a cappella power metal band van Canto.
A resident of the Isle of Man since 1988, John Rhys-Davies provides the introductory voice-over to the Island's Castle Rushen, one of the best-preserved medieval fortresses in the British Isles. In 2018, he lent his voice to the Isle of Man's tourism commercial.
Rhys-Davies voice was recorded for some of the callouts in the 1993 Williams SuperPin Indiana Jones: The Pinball Adventure.
In the 2023 video game The Lord of the Rings: Return to Moria, Rhys-Davies reprises the role of Gimli and narrates the opening scene.