A cementing system was developed with advanced performances for wellbore zonal isolation in the Gulf of Thailand. Wells in the area are located in shallow water and characterized as deep and hot, with low fracture gradients, with deviated wellbore trajectories. Fast-paced drilling activities and working within the offshore logistical parameters further challenge cementing operations and slurry designs. The paper will discuss laboratory test results and a case history focusing on the significant benefits of a lightweight cement system developed to achieve zonal isolation of wellbores under the given extreme conditions. A sidetrack of a well in the Gulf of Thailand was cemented with the novel cementing system. Cement bond log evaluations confirmed significantly better results in comparison to the cement system used to cement the initial section. These findings were also attributed to the improved slurry performances of the novel cementing system.