A flat specimen and a curved specimen with a thickness of 50 mm were excavated from a large circular wire+arc additive manufacturing (WAAM) mockup. The biaxial internal residual stress distributions in the specimens were measured using the two-cut contour method. The stress distributions in the large circular WAAM mockup were deduced, and the effects of specimen shape and dimension on the remnant stress distributions in the specimens were discussed. The investigated results show that the stress in the circular WAAM mockup has a similar distribution as that in thick multipass joints at the weld centerline, the stress in the curved specimen extracted from a large circular WAAM mockup can reflect the stress distribution trend in the mockup. For specimens excavated from a large circular mockup, the specimen shape has no significant effect on the through-thickness axial stress distribution, while it has a significant effect on the hoop stress distribution.