Advanced ultrasupercritical steam conditions of up to 760uC and 34?5 MPa have been investigated in various programmes around the world over the last two decades. To date, much progress has been made, and three candidate materials, namely ferritic, austenitic and nickel base superalloys, have been investigated for high temperature strength, corrosion resistance and weldability. In an earlier published paper, welding and weldability of ferritic alloys were discussed. This paper considers the unique weldability characteristics for utilisation of austenitic stainless steels in future advanced ultrasupercritical fossil power plant designs and covers topics such as fundamentals of austenitic stainless steel welds, including weldability, filler metals and dissimilar metal welds, and discusses the prognosis for this class of materials for advanced ultrasupercritical fossil fired power plants.