You need an ETA for South Korea if you have a Brazilian passport

Travelers need a travel authorization to visit South Korea for Business or Tourism. Visa-exempt visitors entering South Korea must obtain an Electronic Travel Authorization (eTA). Travelers can submit the eTA application online. Once the application is approved, travelers receive their eTA confirmation electronically. An eTA is electronically linked to a passport and valid for up to 3 years. If travelers receive a new passport, they must apply for a new eTA. A valid eTA is required to board the flight. If the eTA is expired or doesn’t match the traveler’s passport information, travelers will not be able to board their flight. This travel authorization requirement doesn’t apply to the following travelers: -Travelers who transit through South Korea and stay in the airport transit area without going through immigration control for any reason; -Travelers aged 17 and under and 65 and older are exempt from requiring a Korean eTA, but may apply to receive the benefit of not having to complete an arrival card upon entry.