Which Game of Thrones episode is the series' longest by runtime?

The Game of Thrones episode with the longest runtime is “The Long Night.”

It is the third episode of season 8 and the series’ 70th episode overall. First aired on April 28, 2019, it runs about 81 minutes in commonly cited episode listings, making it longer than the 80-minute “The Iron Throne” and every earlier episode.

The episode is set almost entirely at Winterfell during the battle between the living and the Army of the Dead. It features the deaths of major characters including Theon Greyjoy, Jorah Mormont, Lyanna Mormont and Eddison Tollett, while Arya Stark kills the Night King. The title also echoes the ancient Long Night described in Westerosi history.

Some listings give the runtime as 82 minutes because of rounding or platform metadata, but that does not change the answer. “The Bells” and “The Iron Throne” are among the other unusually long final-season episodes, while “The Winds of Winter” was the previous record-holder.