Two marine euplotid ciliates, i.e. Euplotes cristatus Kahl, 1932 and E. minuta Yocom, 1930, were collected from the public waterfront of Incheon on the Yellow Sea and from the Songjeong Beach, Busan, in the Strait of Korea, respectively. These two species were verified as unrecorded species in Korea. These species were described based on live observation, protargol impregnation, and silver nitrate impregnation. In addition, the small subunit ribosomal DNA (SSU rDNA) sequences of the two species were compared with previously known sequences of the Euplotes species. Euplotes cristatus has an elongated oval form, size in vivo of $60-84{ imes}38-68;{mu}m$, 35-50 adoral zone of membranelles (AZM), 10 frontoventral cirri (FVC), 5 transverse cirri (TC), 4-5 caudal cirri (CC), 8 dorsal kineties (DK), 10-16 dorsal cilia of middle DK, and silverline system of single-vannus type. Euplotes minuta has a small ovoid form ($44-53{ imes}26-35;{mu}m$ in vivo), 31-41 AZM, 10 FVC, 5 TC, 4 CC, 9 DK, 10-12 dorsal cilia of middle DK, and silverline system of single-vannus type.