Pakistan’s Tanker Fleet: A 254% Dark Activity Surge in the Strait of Hormuz

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The strikes on Iran on 28 February 2026, and the escalation that followed, changed the operating environment for every fleet moving through the Gulf. To establish how one national fleet actually responded, MIOC analysts ran a 17-month lookback on Pakistan-flagged and Pakistan-linked vessels across three domains: tanker dark activity, ship-to-ship (STS) behavior and Iran-linked convergence, and small-vessel evasion patterns.

The findings split cleanly. The tanker fleet changed behavior sharply and immediately. Ship-to-ship and small-vessel activity declined over the same period.

What Happened

Between March 2025 and 28 February 2026, the Pakistan-flagged and -linked tanker fleet averaged 60.9 dark hours per month, with 95% of that activity concentrated in the Persian Gulf. After 28 February, monthly dark hours rose to 215.4 — a 254% increase — and the geography inverted. Persian Gulf dark activity ceased entirely. The Gulf of Oman/Strait of Hormuz transit zone became the primary concentration at 58% of dark hours, with the Red Sea (24%) and the Arabian Sea off the Pakistan coast (14%) emerging as secondary zones.

The shift is visible at the vessel level. Three tankers commenced dark operations after 28 February from zero prior activity. Over the same window, two other Pakistan-flagged-and-linked vessels pulled back or ceased dark operations. The increase began sharply in March 2026 and was sustained through July.

Timing offers additional context: the geographic pivot toward the Strait of Hormuz followed the U.S. naval blockade of Iranian ports, effective 13 April 2026. Windward assesses with high confidence that the pattern reflects fleet-level operational redistribution in response to regional tensions rather than isolated vessel behavior.

What It Signals

A surge of this shape typically prompts three follow-on hypotheses: 

1. The fleet is converging with Iranian or sanctioned counterparties.
2. A home port — in this case Karachi — is functioning as an evasion hub.
3. The evasion toolkit is spreading to smaller craft. MIOC tested each against 17 months of data. None held.

Iran convergence: zero. Across the full lookback, no Iran-flagged vessel and no Windward Compliance Risk Level 3 vessel was detected meeting a Pakistan-linked vessel. STS meetings declined 44% after 28 February, from 95.3 to 53.2 per month.

Karachi is not assessed as a sanctions-evasion convergence zone. It accounted for 12% of STS meetings before 28 February and 5% after. A decrease. UAE and Saudi waters dominated throughout, holding 55–60% of meetings.

Small-vessel patterns showed no escalation. Dark events per vessel per month declined 17% (2.47 to 2.06), and MMSI changes remained rare.

The counterparty picture reinforces the assessment. The only notable STS counterparties were three Saint Vincent and the Grenadines-flagged, Pakistani-linked service vessels which first appeared in January 2026, pre-dating the escalation. None carries a Windward Compliance Risk Level 3 designation. The single new post-escalation pattern is a Monaco-flagged vessel, which recorded seven meetings in April–May 2026.

The conclusion: 28 February is an inflection point for the tanker fleet only. The regional escalation triggered tanker dark activity and a geographic reorientation toward the Strait of Hormuz. It did not catalyze Iran-linked STS operations, it did not activate Karachi as a convergence zone, and it did not push evasion behavior into the small-vessel fleet.

This analysis was produced by Windward’s Maritime Intelligence Operations Center (MIOC), based on a 17-month lookback (March 2025 – 6 August 2026) of Pakistan-flagged and Pakistan-linked vessels, using multi-source detection on the Windward Maritime AI™ Platform.

Report produced by MIOC Team Lead Matthew Mueller.

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