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Simple Summary: Bluetongue (BT) is an economically significant disease in ruminants, transmitted worldwide by Culicoides midges, with the causative agent being the bluetongue virus (BTV). Traditionally prevalent in tropical regions, its geographic range is expanding due to climate change. Despite its global impact, research on the BTV in the Republic of Korea (ROK) is scarce. In this study, we aimed to assess BTV seroprevalence and conduct genetic analyses on isolates from South Korea. Out of 5824 cattle samples, 194 (3.33%) showed BTV antibodies, and 2 out of 1095 (0.18%) goat samples were positive. BTV RNA analyses of 422 high-risk area cattle samples revealed 51 (12.1%) positive cases. The virus was successfully isolated from one sample, identified as serotype 3 based on segment 2 analysis. This study presents the first full-genome sequence of a South Korean BTV serotype 3 isolate, serving as a global reference. These data aid in understanding phylogenetic relationships among BTV strains and recognizing reassortment events, enhancing our knowledge of this developing virus. The bluetongue virus (BTV) is a significant animal pathogen with economic implications in the ruminant industry. Despite global reports on BTV detection and epidemiologic investigations, limited studies have focused on the virus in the ROK. In this study, BTV epidemiological research was conducted on blood samples from cattle and goat farms across nine regions during 2013–2014. The results showed that 3.33% of bovine blood samples (194/5824) and 0.19% of goat blood samples (2/1075) tested positive for BTV antibodies using ELISA. In Jeju-do, BTV RNA amplification occurred in 51 of 422 samples (12.1%) using real-time reverse transcription (RT-qPCR). The isolation of one sample revealed it as serotype 3, as indicated by the sequence of segments 2 (Seg-2) and 6 (Seg-6), associated with the eastern BTV topotype. However, based on Seg-1, -3, -4, -5, -7, -8, -9, and -10 analyses, the BTV-3/JJBB35 strain is more closely related to distinct BTV strains. These findings imply BTV circulation and that the Korean-isolated BTV might originate from Asian BTV strains due to multiple reassortment events. This study provides foundational data for ongoing BTV monitoring and disease-control policies in the ROK. [ABSTRACT FROM AUTHOR]