After President Yoon Suk Yeol of South Korea briefly imposed martial law in December, many young people in the country took to the streets for the first time. They spent months calling for his removal as they sang protest anthems and attended marches in the freezing cold holding K-pop light sticks and custom-made flags.

When Mr. Yoon was later impeached and removed from office, young protesters felt that their work had paid off. But as Election Day approached, some of them felt disenchanted by the candidates on the ballot.

“My one thought on this election is disgust,” said An Ye-young, 20, who is preparing for the college entrance exam. She joined the demonstrations again Mr. Yoon in December, her first time as a protester.

“It’s a feast with nothing to eat,” she said, speaking over the weekend after casting her ballot early.

For many young South Koreans, the candidates running on Tuesday are not addressing some of their key issues: youth unemployment, pension reform, and discrimination and abuse against women.

Young people in South Korea face a tough job market. The unemployment rate among people 15 to 29 rose to a four-year high of 6.8 percent in the first quarter of this year.