Daejang–Hongdae Line

Daejang–Hongdae Line is a subway line under construction in South Korea. It will connect Daejang-dong in Bucheon with Hongik University Station in Seoul. First formally proposed in 2014, it passed a financial feasibility study in 2021 and groundbreaking occurred in late 2025. It will be the first subway line in Korea to combine build-transfer-operate and build-transfer-lease investment models. The government will contribute 1 trillion KRW and Hyundai Engineering and Construction will contribute 1.1 trillion KRW and share revenue.
Several line extension proposals started to undergo evaluation in early 2026.