Bethan Roa was a joined male Trill in the 24th century.

In his later years, Bethan Roa resided on Shal Tul, a Federation colony world. An elderly man by 2372, Bethan Roa's humanoid mind began to fail. Wanting to hide his infirmity from the Trill Symbiosis Commission, he began taking human drugs to restore his mental faculties. However, these had the side effect of dissolving the host-symbiont bond, and damaging the symbiont.

Bethan Roa used this procedure help the criminal Verad steal the symbiont from Duhan Vos, and had planned to sell the opportunity for temporary joining to Vos to other desparate unjoined Trill. However, Verad instead killed Bethan, and used Roa in the same way.

Bethan had a granddaughter named Lyrrin, who was a student of Ziranne Idaris. (DS9 short story: "Reflections")