Local corrosion of the welds of offshore structures in ice seas is a serious problem as the paint and cathodic protection system of the structures are damaged by the impact of ice. For this reason, the fabrication of offshore structures requires the following considerations ; (1) Local corrosion resistance of welds. (2) Excellent low temperature toughness of base metal and welds. (3) Steel products, welding materials and fabrication methods, considering weldability for wide range of welding conditions from small heat input for repair welding to large heat input for high productivity. In this paper, development of better quality steel products, welding materials, welding methods and the properties of the welds which satisfied the above requirements are reported.