Wave energy comprises the most abundant resource among the marine renewable energy in the world. Offshore Taiwan, it is also one of the prior marine energy resources and higher nearshore wave energy resources are located in the northeastern (NE) waters. Thus, to facilitate the development of the wave energy conversion technology, a permitted field-test site
offshore Keelung was established in 2011. The associated wave energy resources had been collected with a data buoy being deployed at the offshore boundary of the test site since 2012. This study presents the analysed results from May 2012 to May 2015. Typical joint probability distributions between wave height H and period T in four seasons and monsoon seasons were first shown. The calculated monthly variations of averaged wave energy resources were also presented. The results clearly illustrate that in the NE Monsoon season (Oct. to next March) waves are higher and longer resulting in average wave power density to be about 15 kW/m with directions from ENE to NE.