Maritime operations through the Strait of Hormuz are transitioning into a new "darker" stage as many ships are transiting without AIS signals.

Data providers recently highlighted that ships have exited the waterway, but their data is no longer consistently captured through AIS signals.

The number of vessels transiting without broadcasting their position surged by roughly 600% between 19 April and 3 May, according to a report by TradeWinds.

Over that same window, overhead satellite imagery detected continued commercial throughput even as AIS readouts suggested the strait was largely inactive.

Vessel movement without AIS signals was noted at multiple sites, among them Larak Island, Kharg Island, Bandar Abbas, Fujairah, and the strait's northern passage. The data includes tankers and container vessels.

The decline in maritime visibility has been compounded by electronic interference. In a single 24-hour window, close to 470 ships experienced GPS jamming in the waters near Fujairah and Khor Fakkan, deepening an already fragile tracking environment.

Overhead surveillance additionally exposed a growing gap between what AIS data reports and what is physically present on the water.

Data collected in early May identified a substantial number of commercial-size vessels in the area, the majority of which were operating without AIS transmission.

Several factors may explain the rise in dark transits: avoiding detection, concealing routes or cargo, and adapting to an increasingly uncertain operating environment.