Maritime traffic through the Strait of Hormuz remains steady in overall volume, but vessel behavior is becoming more inconsistent. Ships continue to transmit AIS signals during transits, maintaining full visibility, yet deceptive practices are increasing elsewhere in the Gulf, according to Windward.
On April 28, transit levels stayed consistent, with all vessels broadcasting AIS while crossing the strait. Meanwhile, the total number of ships operating across the wider Gulf dipped slightly, even as instances of “dark” activity rose notably, suggesting a renewed dependence on concealment tactics despite adherence to visibility requirements during passage.
Meanwhile, East of Hormuz, dark tanker positioning near Chabahar continues to build.
At a glance
Hormuz transit holds at 13 crossings, all AIS-visible with no dark activity.
Gulf vessel presence declines to 890, indicating a slight contraction.
Dark activity rises sharply to 148 events, signaling increased deception.
Chabahar cluster expands with five dark tankers holding 7–8M barrels capacity.
Iranian-linked vessels intensify AIS spoofing to mask crude loading.
The system reflects visible transit alongside growing concealment and evasion
Transit holds steady with full visibility
Transit activity through the Strait of Hormuz remained steady on April 28, maintaining moderate volumes under full transparency. A total of 13 vessels crossed the Strait, including 4 inbound and 9 outbound transits. All movements were AIS-visible, with no dark transits recorded.
Inbound and outbound transits through the Strait of Hormuz, April 28, 2026. Source: Windward Maritime AI™ Platform.
Inbound traffic included one Panama-flagged bulk carrier and three cargo vessels, one flagged to Comoros and two to India. Outbound traffic consisted of two tankers flagged to Panama, two bulk carriers flagged to Panama and China, and five cargo vessels, with one flagged to Antigua and Barbuda, two to Iran, and two to Comoros.
All transits were routed through the Northern Corridor.
A notable movement included a Japanese-owned, Panama-flagged VLCC transiting outbound without Iranian linkage, reinforcing that non-sanctioned commercial traffic continues to move through the Strait under current conditions, even as Iran-linked activity remains constrained.
Gulf activity contracts as deception surges
Total vessel presence across the Gulf declined slightly to 890 vessels, continuing the gradual contraction seen in recent days. Panama remains the dominant flag state with 142 vessels, followed by Iran (93), Comoros (83), the UAE (74), Marshall Islands (72), and Liberia (67).
Fleet composition includes 144 bulk carriers, 136 product tankers, 79 crude tankers, 64 container ships, 40 LNG and LPG carriers, and 33 chemical tankers.
In contrast to the modest decline in vessel count, dark activity surged to 148 events, marking a significant increase compared to the previous day.
This divergence points to a clear shift in behavior. While overall traffic is easing, vessels are increasing reliance on concealment and deceptive shipping practices, adjusting to sustained enforcement pressure rather than reducing activity outright.
Blockade impact on dark vessel behavior
Dark vessel positioning around Bandar Abbas and the Larak Island chokepoint provides a clearer view of how the blockade is shaping movement patterns.
At Bandar Abbas, dark vessel concentration remains elevated. Multi-source detection shows a dense cluster of tankers and bulkers anchored in the deepwater channel between the mainland (Bandar Abbas / Shahid Rajaee) and Qeshm Island. Additional clusters are positioned along the Qeshm shoreline, with a thinner spread extending east toward the Strait of Hormuz.
This spatial pattern is consistent across multiple collections and reflects sustained loitering rather than active transit. The area continues to function as a dual-use anchorage, supporting both commercial staging and IRGC-N co-located activity under constrained conditions.
At the Larak Island chokepoint, the pattern is notably different. Dark vessel detections form a narrow north–south ribbon hugging the Iranian coastline, particularly along Bandar-e Charak and the western shore of Larak Island. There is minimal presence in open deep water.
Between April 22 and April 27, a measurable decrease in dark vessel movement was observed at this chokepoint. This suggests reduced transit of non-AIS vessels into and out of the Arabian Gulf.
The reduction aligns with the effects of the U.S. blockade. While vessels continue to stage and cluster within Iranian-controlled waters, fewer are attempting dark transit through the chokepoint itself.
Taken together, the pattern indicates a shift from movement to containment. Dark vessels are still present at scale, but are increasingly concentrated in controlled anchorage zones rather than actively transiting, reflecting the growing impact of enforcement on routing decisions.
…Windward highlights.