A beach in eastern Thailand was turned into a make-believe war zone for the U.S. Navy SEALs and the Thai and South Korean marines, with more than eight hundred of them storming onto the Hat Yao beach in Rayong province on Thursday, according to a feature on the Washington Post.

The joint war games are held on a yearly basis, with this year’s exercises focusing on peacekeeping operations and humanitarian and disaster responses. The annual joint military exercise is on its 29th year this year and has been given the code name Cobra Gold. According to the article, the participation of the United States implies that the country “will have a continued presence in the Asia-Pacific region.”

This is the first year that South Korea joined in the exercises, which are also participated in by the marines of Singapore, Japan and Indonesia. There will be 11,500 military personnel participating in the war games.