Carry-on baggage with a total size not exceeding 115 cm and 12 kg plus one personal item (handbag, laptop) is always free of charge.
Checked baggage is free even on the lowest fares, and you can usually carry a suitcase up to 23 kg; on flights to America you can carry two bags (each up to 23 kg) and on domestic flights up to 20 kg.
Sports equipment up to 23 kg counts as one regular checked bag.
Korean Air only carries dogs, cats and pet birds.