Bird-beak square hollow section (SHS) steel joints have been increasingly used in construction in the past decades due to its desirable structural behaviour and aesthetic appearance. However, corrosion is a common problem in steel structures causing structural deterioration. This paper presents an experimental investigation into the effects of uniform corrosion on the performance of diamond bird-beak SHS steel joints. The research offers a detailed analysis comparing the influence of corrosion on both the weld and base material, focusing on the joint’s compressive strength after corrosion. In the experiment, bird-beak joint were tested at non-corroded and corroded conditions with two corrosion levels (10% and 20%). The findings revealed that as corrosion levels increase, the weld corrodes more significantly than the base material. Concurrently, the compressive strength of the joint decreases with increasing corrosion severity. For joints subjected to lower corrosion levels, the deterioration of the weld has a less significant effect on post-corrosion compressive strength compared to that of the base metal.