The three-week exercise, which began in PyeongChang, South Korea, on December 4, involves more than 220 Marines from each country who train together in the sub-zero temperatures common in the mountainous region.
The two countries have staged joint winter drills each year since 2013.
The troops were semi-naked in the snow performing star jumps, push-ups, and other physical tests, whilst there is also an emphasis on team bonding and building camaraderie between the US and their South Korean allies.
They practiced snow-based stealth manoeuvres in camouflage high in the Korean mountains before living out action-hero fantasies and taking part in skiing and hand to hand combat activities.
Throughout, both sets of troops appeared in high spirits despite the freezing surroundings.
The exercise emphasises the close links between the US and South Korean governments, especially in light of the growing threat from North Korea.
South Korean Marine Corps Commandant Lt. General Jun Jin-goo told the marines: “You are a symbol of the robust South Korea-U.S. alliance, overcoming the severe cold with comradeship.
“Let’s defend the Republic of Korea (South Korea) firmly on the basis of hot comradeship and strong combat power of the allies’ Marine Corps.”
A spokesman for the US marine unit, the III US Marine Expeditionary Force, told the Yonhap news agency: ”This exercise has been held with a focus on enhancing the combined combat capabilities of the South Korean and US Marine Corps in winter war conditions under which temperatures drop down to about minus 20 C.”
South Korea’s armed forces are also training in the area ahead of providing security support to next February’s PyeongChang Winter Olympic Games, which will open in the town.