K-ETA is an electronic travel authorization for nationals of visa-free countries who wish to visit South Korea for tourism, family visits, or non-profit business activities without obtaining a visa.
A Korean tourist visa, on the other hand, is intended for foreign nationals who are not eligible for visa-free entry or who otherwise need a visa to visit South Korea for tourism.
You can apply for K-ETA through ETAPORTAL, while Korean tourist visa applications are generally submitted through a South Korean embassy, consulate, or designated visa application center.
The permitted length of stay under K-ETA depends on the visa-free entry rules for each nationality, while the length of stay under a tourist visa depends on the conditions of the visa issued.
Neither K-ETA nor a Korean tourist visa automatically guarantees entry into South Korea.
The final decision is made by immigration officers upon arrival, so travelers should check the entry requirements for their nationality and purpose of visit before traveling.