Fluid valve apparatus having enclosed seals are disclosed. An example fluid valve includes a movable flow control member positioned between an inlet and an outlet of a fluid flow passageway of the fluid valve. A retainer is removably coupled to the flow control member such that the retainer and the flow control member define a sealing cavity when the retainer is coupled to the flow control member. A seal is positioned within the sealing cavity to define a sealing surface of the flow control member. The seal has an inner core composed of a first material, where the core is substantially encased with a sheath composed of a second material different than the first material. The retainer clamps the seal to the flow control member.