The present investigation employed ABAQUS V6.14 software to examine the stability of a marine causeway when using GTRS. GTRS is a geotechnical reinforcement system consisting of geotextile tubes in the core of a marine causeway. An additional aim of this study is to provide a comprehensive understanding of the behavior of this system in diverse geotechnical environments. Many configurations of GTRS were investigated. The effect of the filling pressure, size of units, the number of units, and the type of filling material have been investigated. The filling pressure was implemented under three different values of 0 kPa, 20 kPa, and 40 kPa; it is worth mentioning that several preliminary models have been created to simulate the filling process of the geotextile tubes to have its deformed shape, two different diameters are employed; 2.00 m and 3.50 m, number of units was changed from 1 to 3, depending on the capacity of the core area. Three different filling materials were employed in the study, i.e., local soil, dense sand, and concrete. The results showed that filling pumping pressure does not significantly affect the stability of the marine causeway. The previous finding was opposite to the effect of the units' number, which has a high degree of influence on the causeway stability. Also, using larger sizes of geotubes is advised during the designing stage. Moreover, using concrete or even improved soil as a filling material obviously gives better performance for the causeway stability than using the same soil as a filling material.