Cabin crews are now expected to focus on the safety of passengers and their own before descending, it said in a statement as cited by the Korea Times newspaper.
In May a Singapore Airlines flight was hit by turbulence so bad that one passenger was killed and dozens of others were injured.
Earlier Korean Air crews stopped services only 20 minutes before landing.
Turbulence is always a threat during descent due to the large temperature differences between altitudes.
The global aviation industry reported that incidents of turbulence doubled in the first quarter of 2024 compared to five years earlier.
Singapore Airlines too has new restrictions including the suspension of in-flight meal service when the seatbelt sign is switched on.
Its flight SQ321 experienced sudden extreme turbulence during the breakfast service while flying over the Irrawaddy Basin in Myanmar.
A 73-year-old British passenger died of a suspected heart attack while some others sustained spinal cord, brain and skull injuries after they were hurled around the cabin.