THE world's deepest metro system is the Pyongyang Metro in North Korea which is 110 meters deep. The tunnel was built as part of an underground military facility. THE world's deepest metro, underground station is the Arsenalna Station on the Kiev Metro in Ukraine, at 107 meters deep.

As of 2026, the title for the deepest public transport system in the world is held by the Chongqing Rail Transit in China, specifically the Hongyancun Station on Line 9, which reaches a staggering depth of 116 meters (381 feet) underground. It surpassed the previous record-holder, the Arsenalna Station in Kyiv, Ukraine, which sits at 105.5 meters deep and was built into a hillside. Another notable deep system is the Pyongyang Metro in North Korea, which averages over 110 meters in depth and was designed to double as a bomb shelter during times of conflict. The Saint Petersburg Metro in Russia is also among the deepest on average, with its Admiralteyskaya station reaching 86 meters deep. These extreme depths are often necessitated by local geography, such as the need to pass under deep riverbeds or navigate unstable soil layers. Navigating these stations typically requires a series of massive escalators; for example, the ride to the platform at Arsenalna takes approximately five minutes.