The International Conference on Synchrotron Radiation Instrumentation (SRI) is a unique and significant international forum held every three years in the community of synchrotron radiation (SR) and free electron lasers (FEL). It is the prime forum for fostering connections between cutting-edge synchrotron radiation instrumentation, science, and the requirements of the user community. The SRI 2021 had originally been scheduled to take place in Hamburg in summer 2021. Due to the COVID-19 pandemic, it was postponed to 2022 and held as an online event.More than 1160 international participants from 25 countries met virtually at the SRI 2021. In nearly 290 talks and 450 posters, latest results were presented. Although it was an online-only conference, lively discussions took place in the nearly 40 parallel sessions, and the eight poster sessions were also very well attended.The main topics of the SRI conference were: new SR and FEL facilities, update plans of these facilities, and recent developments in various instrumentation areas like beamline design, X-ray optics, sample environments, detectors and spectrometers, data acquisition, and data analysis techniques or automation. These innovations contributed to new results for a wide range of experimental techniques and scientific applications such as X-ray scattering and spectroscopy, bio- and scanning imaging, structural biology crystallography, coherent techniques, or in-situ/operando methods. A dedicated session concerned industrial applications of synchrotron radiation.The field of synchrotron radiation instrumentation is currently seeing very active development due to various factors. Firstly, the number of SR sources world-wide is increasing significantly, with new sources in particular in Europe and in Asia. Secondly, a new generation of storage rings with new multi-bend achromat lattices are being implemented at a growing number of existing facilities. These facilities offer a significant increase of brilliance and coherence and thereby lead to new and improved applications of synchrotron radiation, in particular in the areas of imaging and high spatial resolution. Thirdly, the increase of soft and hard X-ray FEL sources worldwide and the maturation of their experimental techniques and scientific applications is the background for a strongly increasing number of developments for ultrafast time-resolved investigations of dynamic behaviour of materials and reactions. Most of the keynote speakers and many invited and contributed talks or posters at the conference showed new results directly related to these three major developments.Lists of International Advisory Committee (listed by facility), Scientific Programme Committee (listed by facility), Local Organising Committee (listed by facility) are available in this PDF.