A majority of India-bound commercial vessels transiting the Strait of Hormuz are switching off their tracking systems, likely to reduce exposure to potential Iranian attacks, according to maritime data.
Data from maritime intelligence firm Kpler shows that nearly 62% of tankers and cargo vessels sailing from the Persian Gulf to India turned off their transponders while crossing the strait.
Ships typically use Automatic Identification System (AIS) transponders to broadcast their identity, location and destination. However, in high-risk environments, vessels sometimes stop transmitting this data to keep anonymity. This practice is known as "going dark".
Vessels flagged to countries perceived as aligned with the West or unfriendly to Iran face heightened risk in the waterway. Shipping patterns indicate that such vessels seem to be using the Oman-side shipping lane, which is backed by the United States and Oman but not recognised by Iran. In contrast, ships using the Iranian traffic separation lanes typically keep their transponders on, although some have also gone dark even while transiting under Iranian monitoring.
Between May 1 and June 25, a total of 73 ships bound for India passed through the strait, of which 45 sailed without transmitting location or identity data, according to Kpler.
Only four India-flagged vessels made the transit during this period, and two of them withheld their identity and routing information. The remaining two crossed through both Iranian and Oman-side lanes while continuing to broadcast their details.
In a broader dataset, at least 69 India-bound vessels - including tankers and cargo ships flagged to countries such as Panama, Liberia, the UAE and the Marshall Islands - were observed switching off their transponders in the strait. Of these, 14 used the Oman-side route, while 10 crossed via Iran-controlled lanes, indicating that dark transits are taking place across both corridors.
Confusion and shifting rules
Shipping conditions in the Strait of Hormuz have grown increasingly uncertain since the conflict escalated in late February, with Iran frequently altering transit guidance and, in some cases, targeting vessels after granting passage clearance.
In mid-April, the India-flagged VLCC Sanmar Herald was attacked near Larak Island, where Iranian forces regulate maritime traffic. An audio clip that later circulated captured the vessel's captain stating that clearance had been granted by Iran's Islamic Revolutionary Guard Corps (IRGC) navy before the incident.
In early May, several vessels were observed using a route hugging Oman's coastline. This corridor was later endorsed by US forces as part of an escorted transit arrangement and subsequently recognised by Oman and the United Nations' International Maritime Organization (IMO).
Although US and IMO-backed escort operations were scaled back within days of their launch, ships have continued using the route, often with their transponders switched off.
Despite being considered relatively safer due to its proximity to Omani waters and the presence of US naval forces, the route has not been free of incidents. In mid-May, an India-flagged cargo vessel sank near Limah, Oman, following what was reported as a suspected Iranian attack.
