In response to the rapidly changing industry caused by climate change, the Korean government has set a goal of supplying 3 million tons of green hydrogen by 2050. This study aims to determine the leveled cost of hydrogen (LCOH) resulting from floating offshore wind power generation. Initially, we created a numerical model to represent the power curve for large-capacity offshore wind power generation. Additionally, we accounted for the variability in electrolytic cell efficiency by modeling predictions based on real PEMEC parameters using the Aspen Custom Model. The power-hydrogen quantity was then predicted using Aspen Plus. A comparison is also made regarding the transportation of gaseous hydrogen and liquid hydrogen. Gaseous hydrogen is produced through pipelines, while liquid hydrogen is produced using a modified Claude cycle and transported via trucks. Finally, a Techno-economic analysis was conducted, considering the net present value (NPV) derived from capital expenditure (CAPEX) and operating expenditure (OPEX) throughout the entire process. The analysis of LCOH indicated that the most economically viable option for the region with the lowest LCOH per kg is the supply of liquid hydrogen, priced at $11.04/kgH2. Our sensitivity analysis also reveals that while liquid hydrogen is more cost-effective at up to 250 MW, gaseous hydrogen becomes cheaper as its scale exceeds 500 MW because of its greater sensitivity to production volume.