Son is already in South Korea continuing his rehabilitation from a wrist injury that was supposed to keep him out of action for the rest of the season.
The 27-year-old suffered the injury when scoring twice in a 3-2 victory at Aston Villa back in February.
All able-bodied South Korean men are required by law to complete a 21-month service in the military before turning 28.
Son however had his service shortened for captaining South Korea to a gold medal in the 2018 Asian games.
"The club can confirm that Son Heung-min will commence his mandatory military service in South Korea this month,” a Tottenham Hotspur statement read.
"The forward arrived back in his home country at the end of March where he is currently in quarantine. Our medical staff are in regular contact as he concludes his recovery after fracturing his arm in our 3-2 win against Aston Villa on February 16 and continues to train.
"Sonny had surgery on his arm in South Korea before returning to the UK at the end of February to continue his rehabilitation, prior to the initial announcement of the professional game in England being suspended as a result of the Covid-19 pandemic.
"The Premier League has since announced that the 2019/20 season will only return when it is ‘safe and appropriate to do so’ and is under constant review.
"Son will return to London following the conclusion of his military service in May."
Before the season was halted, the former Bayer Leverkusen forward made 32 appearances in all competitions, scoring 16 goals.
