Ship motion is an important influencing factor in passenger ship evacuation that affects the entire evacuation process by reducing an individual’s walking speed. This study aims to quantify such effects in ship berthing and sailing operations by collecting experimental data to support passenger ship evacuation decisions. The study utilized Dalian Maritime University’s training ship to conduct human walking experiments to study the influence of ship motion on passengers’ normal and fast walking speeds. It was found that during the berthing period, an individual’s normal walking speed was 1.28–1.68 m/s, and the fast walking speed was 1.50–2.14 m/s. During the sailing, the ship’s rolling motion reduced the normal walking speed by 3.8%–10.3% and the fast walking speed by 3.7%–14.0%. Due to the influence of ship rolling, the higher the deck and the farther away the rolling centre is, the smaller the athwartship and fore-aft walking speeds. Athwartship walking was slightly faster than fore-aft walking. Similarly, in the normal walking mode, the athwartship walking speed was 1.6%–3.7% faster than fore-aft walking, while in the fast walking mode, the athwartship walking speed was 0.8%–4.9% faster than fore-aft walking. Furthermore, during the berthing period, the average walking speed of the younger group was 24.1% higher than that of the older group. Finally, during the sailing, the speed reduction ratio of an individual’s walking speed was 86.0%–96.2%, and the value decreased as the deck height increased.