The present invention provides an insulated fluid conduit useful in facilities in which a hot fluid susceptible to deleterious phase changes in response to heat loss to a cold environment is transported. Such conduits may be particularly well suited to improve thermal control in subsea hydrocarbon production operations in which hot production fluids may undergo deleterious phase changes as a result of heat loss to the cold subsea environment. The fluid conduit includes an insulating material containing a silicone rubber and a phase change material such as octadecane. One or more barrier layers inhibit migration of the phase change material from the insulation layer and into the environment. In one or more embodiments, the phase change material is present as a microencapsulated phase change material.