Silicon Photonics is widely acknowledged as a gamechanging technology, driven by the needs of datacom and telecom. Silicon Photonics builds on highly capital-intensive manufacturing infrastructure, and mature open-access silicon photonics platforms are translating the technology from research fabs to industrial manufacturing levels. To meet the current market demands for silicon photonics manufacturing, a variety of openaccess platforms is offered by CMOS pilot lines, R&D institutes and commercial foundries. This paper presents an overview of existing and upcoming commercial and non-commercial openaccess silicon photonics technology platforms. We also discuss the diversity in these open-access platforms and their key differentiators.