| Conflict: | Battle of Haeju |
| Partof: | the Korean War |
| Date: | September 10, 1950 |
| Place: | off Haeju Bay, Korea, in the Yellow Sea |
| Result: | United Nations victory |
| Units1: | Republic of Korea Navy |
| Units2: | Korean People's Navy |
| Strength1: | 1 patrol boat |
| Strength2: | 1 minelayer |
| Casualties1: | none |
| Casualties2: | unknown human casualties, 1 minelayer sunk |
The Battle of Haeju was a small naval battle during the main phase of the Korean War.
Off Haeju Bay in the Yellow Sea, on September 10, 1950, days before the Battle of Inchon, a South Korean navy patrol boat, PC-703, encountered a North Korean navy minelayer sailing vessel. After a brief fight, the North Korean minelayer was sunk with a loss of all crew and no South Korean casualties were reported.
After the minelayer's sinking, PC-703 discovered that the sunken vessel had laid a mine field at the mouth of the Haeju Man and then reported to base the location of the sea mines. Two days later on September 12, PC-703 encountered three small transports and sank them. The three supply vessels were most likely unarmed.