The Division of Vectors and Parasitic Diseases of the Korea Disease Control and Prevention Agency operates a malaria vector (Genus Anopheles) surveillance system to provide warnings and alerts. Surveillance was conducted at 36 sites in Incheon-si, Gyeonggi-do, and Gangwon-do, and 14 sites in military bases from April to October 2023. In 2023, the trap index (TI) (number of mosquitoes/traps/days) was 72.4, a 29% decrease from the average of TI past 5 years (2018-2022) and a 2.7% increase from 2022. The TI was Gyeonggi-do (1,761), Incheon-si (593), and Gangwon-do (496), whereas the incidence rates of Anopheles was Gyeonggi-do (58.9%), Gangwon-do (37.5%), and Incheon-si (18.5%). The occurrence pattern of Anopheles showed two peaks: the first at week 26 (9.2) and the second at week 34 (8.1). The 26th-week peak was attributed to Gyeonggi, whereas the 34th-week peak was attributed to all regions. Plasmodium vivax was detected in mosquitoes, totaling 3 pools (minimum infection rate 0.2) at week 28 (1 pool) and week 36 (2 pools). This marked a 2-pool increase compared to 2022 and was detected 9 weeks earlier. And an alert was issued based on the positivity of P. vivax in Anopheles at week 28. Additionally, in 2023, malaria cases were observed to increase by approximately 75% compared to 2022, and the TI and minimum infection rate were also confirmed to have increased. Ultimately, as part of the intervention to reduce malaria in endemic areas, it is necessary to strengthen surveillance and focus on mosquito control and personal protection.