Offshore wind and waves are classified as major marine renewable energy sources. A reliable assessment of wind and wave energy resources is important to study over the Gulf of Thailand (GoT) and Andaman Sea (ADS). In this study, the surface wind and wave heights were used to investigate the offshore wind and wave energy resources over the GoT and ADS. Alternative methods for the assessment of wind and wave resources are through analysis of wind speeds, wave periods, fully developed wave height (Hf) and significant wave height (Hs) using a statistical analysis of 10-year hindcast datasets from QSCAT from NASA associated with WaveWatch-III (WW3) model results from NOAA. A short-term analysis of dynamical simulations and its comparison of the WW3 global model and Simulating WAves Nearshore (SWAN) regional model were also used to investigate the preliminary testing and possibility of offshore wind-wave resources and powers. Results of both models were relatively similar to those of buoys at the offshore locations in a case study of Typhoon Linda 1997 entering the GoT. In this study, the results of WW3 datasets revealed that wind and wave capacities at the lower GoT were in the ranges of 400-800 W m–2 and 1-1.5 kWm-1, respectively. Over the ADS, WW3 model datasets with the QSCAT wind data provided wind and wave powers in the ranges of 300-600 W m–2 and 2-4 kW m–1, respectively. The WW3 and QSCAT combinations, therefore, could be the potential alternative methods for 10-year long-term assessments of wind and wave power.