3D bioprinting is an emerging technology for tissue fabrication;​ however, its application in large tissue fabrication is limited due to difficulty to fabricate at multiple length scales and the slow printing speed resulting in prolonged exposure of cells to unfavorable environment. Herein, we present Fast HydrogeL PrOjection StereolithogrAphy Technology (FLOAT) that enables fabrication of large-scale thick hydrogel tissues containing perfusable vascular channels through a single, rapid printing process. The unique mechanism of FLOAT printing, high-velocity prepolymer flow-enabled continuous hydrogel printing under a very-low suction force, allows the reduction of system complexity and the improvement of fabrication capability over the existing continuous printing methods. We demonstrate the capability of FLOAT for printing a 3D liver model with pre-fabricated perfusable vascular channels with high encapsulated cell viability and functionality as evidence by long term perfusion culture and albumin production by encapsulated liver cells. We demonstrate the good compatibility of the FLOAT with multiple photocurable hydrogel materials and the strategies to optimize the printing material to improve tissue regeneration such as the endothelialization of pre-fabricated vascular channels. Together, these studies show that FLOAT is a promising approach for the fabrication of clinically-relevant sized, vascularized engineered tissues potentially suitable for rapid injury repair and transplantation.