The Trill Diplomatic Corps was a Trill diplomatic body. In 2075, a member of the Diplomatic Corps met with several Vulcans, including T'Pau, who wanted to speak to Lela Dax after the L'Dira attacked Trill. (DS9 - The Lives of Dax short story: "First Steps") Seljin Gandres was an Ambassador in the Diplomatic Corps. He spent several years dealing with the Pakleds on behalf of the organization. (DS9 novel: This Gray Spirit)