The first zoeas of Chinese ditch prawn Palaemon gravieri (Yu, 1930) and carpenter shrimp Palaemon serrifer (Stimpson, 1860) are described and illustrated in detail based on laboratory-hatched material. They are distinguished from those of Palaemon ortmanni (Rathbun, 1902) and Palaemon pacificus (Stimpson, 1860), previously known larvae from Korean waters by the length of the rostrum and endopod of antenna, the shape of the third abdominal somite, and ornamentation of the fifth abdominal somite. Larval characters of the genus Palaemon are revised. A. provisional key to the known first zoeas of Palaemon from Korean waters is given.