The Royal New Zealand Navy resident naval officer, of Dunedin, was one of three New Zealand Defence Force personnel selected to replace those finishing a six-month deployment in Seoul.
Lt-cmdr Marshall (50) will leave New Zealand on April 3 and arrive in the South Korean capital on April 5 - exactly five years to the day since he left the city after a six-month deployment at Camp Bonifas, between September 2007 and April 2008.
It will be his third overseas deployment; his second was a six-month stint in Afghanistan from October 2008 to April 2009.
Lt-cmdr Marshall volunteered for the 12-month posting and was looking forward to the challenge as a senior officer within the ''operations side of things''.
''I'll be based in Seoul and doing quite a bit of work within the demilitarised zone, monitoring the armistice and making sure there are no violations,'' he said.
Since the armistice agreement was signed in 1953, the United Nations Command Military Armistice Commission has been made up of representatives from 16 countries committed to upholding the agreement and supervising the Korean demilitarised zone.
Lt-comdr Marshall said New Zealand had the third largest contribution of countries within the commission, behind the United States and South Korea.
Most of the 9000-odd troops in Seoul's Yongsan army garrison, where he would be based, were American, he said.
''There is still about 30,000 Americans in South Korea. For me, the attraction is the food and culture, and the chance to do something a bit different and more challenging.''
His wife Marie, who recently became the Dunedin RSA Welfare Trust's welfare officer, will stay in Dunedin and visit him in South Korea.
Lt-cmdr Marshall said his Korean was ''basic'', but English was widely spoken and the commission included translators.
