Visible light communication in underwater environments is replacing the RF and the acoustic signals due to its high bandwidth, low latency, and small attenuations. One of the performance degrading factors in underwater channels is the turbulence which is caused by a continuous change in refractive index of water. Spatial diversity can overcome the optical scintillations as well as the pointing errors. This paper evaluates the ergodic capacity and the BER performance of MIMO as well as SSK-MIMO UVLC system in presence of underwater turbulence, modelled by Lognormal, Gamma, and Weibull distributions. The capacity analysis is based upon varying number of transceivers and the water filling algorithm. Impact of spatial correlation is also considered for the capacity analysis. The results find their validation via Monte Carlo simulations. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.