South Korea passport holders need a visa to enter Timor-Leste. You must apply at the Timor-Leste embassy or consulate before traveling. Processing times vary but typically range from 5-15 business days.
A confirmed flight reservation is usually required as part of your visa application documents. Rather than purchasing a non-refundable ticket, you can generate a free dummy ticket from MyJet24 to include with your Timor-Leste visa application.