In optical wireless communication systems, the underwater visible light communication (UVLC) systems is becoming more and more popular. However, due to intrinsic properties of water body, the propagating optical channel can suffer from severe degrading effects, namely absorption, scattering, and turbulence. Here, we aim to improve the UVLC system performance. For this, we propose to utilize an adaptive modulation scheme at the optical transmitter based on the channel conditions. The performance of such system using different modulation schemes such as the pulse position modulation (PPM), the digital pulse interval modulation (DPIM) and the dual-header pulse interval modulation (DH-PIM), are demonstrated to prove the effectiveness of our adaptive UVLC systems.