ABSTRACT FSRU (Floating Storage Re-gasification Unit) project was carried out by MOERI/KIOST during 2008~2013 and they developed core engineering technologies for FSRU. As a key result of the project, time domain dynamic coupled solver for floating body and mooring lines was developed and it was applied to performance analysis of single body FSRU system with catenary mooring lines. This paper extended the research to the multi-body case such as FSRU, mooring lines and LNG carrier. The floating FSRU system is 315 meter long and it has a turret system with nine steel catenary chains. Layout of FSRU and the carrier is assumed to be side-by-side. Higher order boundary element method (HOBEM) and finite element method (FEM) were applied to solve floating body hydrodynamics and mooring line dynamics, respectively. Convolution is used in time domain transform of floating body and Newmark method is applied in time marching in mooring lines. Body-mooring coupled solution is calculated by iterative manner. In numerical analysis, the linkage condition between FSRU and carrier is also considered and motions of two bodies and line tensions of mooring systems are calculated and compared for the cases with or without the linkage system.