Yonas Kibreab as Elio / Other Elio (voice)

Remy Edgerly as Glordon (voice)

Zoe Saldaña as Olga Solís (voice)

Brad Garrett as Lord Grigon (voice)

Brandon Moon as Ambassador Helix (voice)

Jameela Jamil as Ambassador Questa (voice)

Young Dylan as Bryce (voice)

Jake T. Getman as Caleb (voice)

Matthias Schweighöfer as Ambassador Tegmen (voice)

Ana de la Reguera as Ambassador Turais (voice)

Atsuko Okatsuka as Ambassador Naos (voice)

Shirley Henderson as Ooooo (voice)

Naomi Watanabe as Ambassador Auva (voice)

Brendan Hunt as Gunther Melmac (voice)

Anissa Borrego as Ambassador Mira (voice)

Shelby Young as Diplo Ship (voice)

Bob Peterson as Universal Users Manual (voice)

Kate Mulgrew as Museum Exhibit Narrator (voice)

Tamara Tunie as Colonel Markwell (voice)