1. What floating storage is, in one paragraph
Floating storage means oil sitting on a tanker at sea rather than in an onshore tank, and right now it is shrinking for Iran specifically: about 29 million barrels in early September 2026, down from a peak near 90 million barrels in mid-July, according to Kpler data cited by RFE/RL on 8 September 2026. A drawdown like that is watched as an early indicator, not a price signal on its own, because it shows how much of a buffer a blocked seller still has before an export shortfall becomes visible in the market.
The number that matters here is specific to Iran. A separate, larger figure exists for floating storage worldwide, and this page keeps the two apart throughout rather than blending them into one impression.
2. How it is measured, and when it actually pays off
Floating storage is tracked by satellite and AIS ship-tracking data providers, chiefly Kpler, Vortexa and TankerTrackers.com, and each one defines it slightly differently, for example how many days a tanker must sit without a destination port before it counts. That means figures from different providers are not directly comparable, even when they describe the same week.
Storing oil at sea only makes commercial sense when the futures market is in contango, meaning a later delivery month trades high enough above the spot price to cover the tanker's day rate, insurance and the interest tied up in the cargo. When a route is simply blocked, as with Iran's export routes since the current blockade, storage is not a trade at all: it is oil with nowhere to go.
Either way, ships used for storage are pulled out of the freight market, which is one reason tanker freight rates can stay elevated even when overall trade volumes fall. Much of the Iranian floating fleet also draws on the same aging, opaquely owned tankers described in our shadow fleet glossary entry.
3. The numbers, kept apart by scope and date
The table below separates Iran's own stockpile from the global total on purpose; they measure different things at different moments and should never be read as one series.
| Indicator | Value | As of | Source |
|---|---|---|---|
| Iran floating storage, peak | about 90 million barrels | mid-July 2026 | Kpler via RFE/RL, globalsecurity.org, 8 Sep 2026 |
| Iran floating storage, now | about 29 million barrels | early September 2026 | same source |
| Estimated drawdown pace | about 1 million b/d, mostly to China | as of 8 Sep 2026 | same source |
| Persian Gulf loading under blockade | about 220,000 to 255,000 b/d, about 85% below pre-blockade level | since 13 to 14 Jul 2026 | same source |
| Global floating storage, all countries | 91.28 million barrels, down from a revised 138.48 million the prior week | week to 10 Apr 2026 | Vortexa via investinglive.com, 12 Apr 2026 |
| Venezuela floating storage, for comparison | 72.3 million barrels, up 6.6 million since 30 Sep 2025 | 17 Nov 2025 | Vortexa/Braemar via investing.com, 17 Nov 2025 |
The blockade context matters for reading the Iran rows: the Strait of Hormuz itself carried only 8 merchant transits on 13 September 2026 against a normal 85 a day, per straits.live data as of 17 September 2026, and no authority has formally declared the strait closed even as traffic stays far below normal. See our Strait of Hormuz glossary entry for that chokepoint on its own terms.
4. How the current drawdown compares with 2025 and with Venezuela
Iran's floating storage has moved in both directions over the past year, and none of the swings should be read against the global total. Between August and November 2025, before the current blockade, Iranian floating storage grew by about 22.5 million barrels by 17 November 2025, from a starting level of about 36 million barrels, according to Vortexa data cited via a Braemar analysis on investing.com; the source does not give a single closing level, so none is stated here. Venezuela's floating storage stood at 72.3 million barrels on the same date, up 6.6 million since 30 September 2025, a separate sanctioned-oil story running on a similar mechanism.
The build-up that peaked near 90 million barrels in mid-July 2026 and the global figure of 91.28 million barrels in the week to 10 April 2026 look similar in size, but they are not the same measurement: one is Iran alone at a July peak, the other is every country's floating oil in an April week, reported by a different data provider. The investinglive.com report on the global figure explicitly flagged that its April snapshot could already be outdated by the escalation that followed, a caution worth carrying into any single week's number.
5. What a build-up or drawdown says about the coming weeks
A shrinking Iranian stockpile, if the roughly 1 million barrel a day pace holds toward the estimated mid-October 2026 exhaustion window, points to a buffer that is running out, not to a specific price outcome. Once that cushion is gone, an export shortfall that the stockpile had been absorbing would show up directly in available supply, without floating storage left to smooth it over. That is a mechanical read of the buffer, not a promise about what the market will do next.
A move in the global figure in either direction can mean opposite things, and the week to 10 April 2026 shows the drawdown side: it fell by 47.2 million barrels to 91.28 million after a ceasefire announcement, mostly in the Middle East. A build and a drawdown each have two readings: a truce opening up safe passage again, or oil accumulating because buyers have not yet been found. The number alone does not say which, so it is worth reading alongside tanker freight rates and the wider supply picture rather than on its own.
See what a change in crude supply could mean for your own household budget.
Run the calculator6. What floating storage does not mean
Floating storage is not the same thing as a country's strategic reserve, and it is not the days-of-supply figure either. Our strategic reserve glossary entry covers government-owned stock held onshore for emergency release, a policy tool; floating storage is commercial oil sitting on ships, usually because a route, a buyer or a favorable price spread is missing. Our days of supply glossary entry covers a different question entirely, how many days a country's onshore inventories would last at current use, measured in days rather than barrels on water.
The most common mix-up on this topic is treating the global floating storage figure and Iran's own stockpile as the same number. They are not: the roughly 91 million barrel global total from the week to 10 April 2026 and Iran's roughly 90 million barrel peak in mid-July 2026 are close in size by coincidence, measured by different providers at different times for different scopes. A second caution applies across the board: because Kpler, Vortexa and TankerTrackers.com each use their own threshold for what counts as floating storage, treat any single figure as that provider's own reading, not an agreed industry total.