We systematically investigate the bubble-induced performance degradation for underwater optical wireless communication (UOWC) with different bubble sizes and positions. By using different transmit and receive diversities, we investigate the effectiveness of spatial diversity on the mitigation of the bubble-induced impairment to the UOWC link. With the help of a 2 × 2 multiple input multiple output using repetition coding and maximum ratio combining, a robust 780 Mbit/s UOWC transmission is achieved. The corresponding outage probability can be significantly reduced from 34.6% for the system without diversity to less than 1%.