The vessels will arrive by 2010, the Seoul-based company said in regulatory filing yesterday.
The bulk carriers will be new vessels, while the oil tanker is second-hand, a company official, who refused to be identified, said by phone.
Korea Line follows Hanjin Shipping Co in ordering bulk carriers as China's booming demand for iron ore, used in making steel, drives up rates.
The Baltic Dry Index, a measure of commodity-shipping costs on different routes and ship sizes, has risen 46 per cent this year.
Shares of Korea Line rose 0.9 per cent to 87,000 won in Seoul yesterday.
The stock has risen 76 per cent this year, outperforming a 15 per cent gain in the benchmark Kospi index.
Hanjin Shipping, South Korea's largest shipping line, ordered two bulk carriers from Hyundai Heavy Industries Co earlier this month.