This paper presents a hydroelastic analysis of pontoon-, semisubmersible-, and hybrid-type VLFS and its experimental validation. In the analysis, the detailed configuration of the experimental model is considered by using three dimensional finite element (FE) method. Experimental models measuring 15m in length, 3m in width and 0.03-0.23m in draft (depending on whether it is the pontoon and semisubmersible part) are built. The experiment has been made in the wave-basin with the bottom-slope of 1/75. At the same time, a hydroelastic analysis is carried out using the same models as the experimental ones in a wave-basin with flat as well as slanting bottom with slope of 1/75. By comparing the numerical results and experiment, the effect of bottom slope is verified. In the analysis of the semisubmersible part, the effect of viscous damping is considered by using the drag force formula with assumed drag force coefficient of 2.0. A comparison between the experiment and the analytical results indicates that numerical results from the semisubmersible part with additional effects of viscous damping agree better with the experimental results than those without. An experiment using irregular waves is also carried out and compared with the numerical predictions. Finally, the steady drift forces are analyzed using the far-field method and compared with the experiment.