You are probably unaware but foreign nationals, including tourists, are allowed to travel to South Korea. The land of K-Pop managed to prevent a large outbreak without imposing a full lockdown and closing its borders, unlike many countries.
Borders are open to foreign visitors including those from the US, Australia, Canada and the UK, but South Korea has imposed health and safety protocols for international flights. Unlike other countries where a negative COVID test is sufficient in order to pass the border, South Korea learned that exposure to the virus could happen during the flight. Thus, all arriving international passengers undergo health screening at the airport which includes temperature checks.
Moreover, travellers are required to self-isolate or be in quarantine for 14 days and download the Self-Diagnosis Mobile App. While international travellers will handle the cost of their quarantine, the South Korean government will provide food and “care packages” for those who arrive in the country. Once travellers finish their quarantine, they are allowed to move around the country freely.