The experimental realization of multiple-input single-output (MISO) in visible light communication (VLC) has always been difficult due to dynamic channels, complex alignment, and limited capacity. We designed a quantum dot (QD) fluorescent concentrator combined with power domain multiplexing of a non-orthogonal multiple access (NOMA) scheme to provide an estimation-free MISO system. The system supports a large detection area of over 4 cm2 and a sum rate up to 120 Mbps over 2.3-m free space, providing a promising connection for the Internet of things (IoT). The concentrator was further implemented in an underwater environment under insufficient incident power. A record data rate of 120 Mbps has been achieved in a 1.5-m underwater MISO system, with a mean bit error rate of 3.24 × 10-3, which is below the forward error correction criterion.