Superfield description of gravitational couplings in generic 5D supergravity

We complete the N=1 superfield action for the generic system of vector multiplets and hypermultiplets coupled to 5D supergravity, which is based on the superconformal formulation. Especially we clarify the gravitational couplings to the bulk matters at linear order in the gravitational superfields. They consist of four N=1 superfields, two of which are Z_2-odd when the fifth dimension is compactified on S^1/Z_2. This formulation provides a powerful tool to calculate quantum effects, keeping the N=1 off-shell structure.