The 26-year-old is one of three overage players who has been named in South Korea’s Under-23 squad for the tournament starting August 14.
“I feel sorry because Tottenham is my team and I feel very sorry to be leaving my teammates,” Son was quoted as saying by ESPNFC.
Handed a new five-year contract recently, Tottenham agreed to release Son after their opening game at Newcastle on August 11.
“I am playing for my country and that is also important, but honestly I feel very sorry about that. That is what I feel,” he said.
“We can talk about (the national service) afterwards. We haven’t won it already. We are going there to win something, and winning trophies for my country is always good. I don’t travel there for nothing.”
Son and his South Korean teammates would want to erase the pain of World Cup group stage exit by winning gold at the Games in Indonesia.
South Korea lost their opening two matches against Sweden and Mexico — although they went on to beat Germany in their third and final game.
“It was disappointing but we finished well against Germany,” said Son.
“Our country was happy because they were No. 1 in the FIFA rankings and the defending World Cup champions. For me, the tournament was disappointing because I always expect more than the group stage. I wanted to stay longer than we did. But it was a good experience to play at the World Cup and I look forward to playing in another in four years.”
On teammate and World Cup’s Golden Boot winner in Russia Harry Kane, Son said: “Harry Kane is one of the best strikers in the world. That is why he has won the Golden Boot twice in the Premier League and once at his first World Cup.
“He deserved it as well because he worked really hard. He will come back with a lot of confidence and I think he can win another Golden Boot.”