The missiles were launched from a site in the DPRK (Democratic Peoples Republic of Korea / North Korean) province of Gangwon and flew for about 155 miles (250km), according to officials in South Korea.
DPRK has accelerated its missile testing program.
Since firing an intercontinental ballistic weapon last month, Pyongyang has threatened to aim missiles at the US Pacific territory of Guam.
The projectiles were launched at 06:49 on Saturday (21:49 GMT Friday), South Korea's Defence Ministry said.
"The military is keeping a tight surveillance over the North to cope with further provocations", the ministry said.
Thousands of US and South Korean troops are currently taking part in joint military drills, which are mainly largely computer-simulated exercises.
The BBC and Yonhap News Agency have contributed to this breaking story
