Laws in his native South Korea demand that men must complete 21 months of military service before they turn 30.
Failure to do so could lead to imprisonment or even being exiled from the Asian country.
The 26-year-old, who joined Arsenal in August from AS Monaco, has said that his departure from the Emirates Stadium is "inevitable".
"It isn't really possible to be excused. That can't and won't happen, which is another reason I chose to come here," he said.
"I'll have to leave Europe in two years' time and I thought this would be an incredible place to finish. My national service is inevitable and there is no point in thinking anything else.
"I'll still be playing games, but for an army club. I think it'll be difficult to return to Europe after that, although if something interesting comes up, you never know."
Park is still waiting to make his first Premier League appearance for the Gunners.