Here’s the verified, factual picture based on current reporting about what’s happening in and around the Strait of Hormuz amid the U.S.

📉 U.S. and International Advisories on Shipping Through Hormuz

The U.S. Navy has issued strong safety warnings to commercial ships and oil & gas carriers operating in the Persian Gulf, Gulf of Oman, North Arabian Sea, and the Strait of Hormuz.
According to Reuters reporting, the U.S. military said it cannot guarantee the safety of neutral or merchant shipping in these waters due to ongoing military operations, and advised vessels to avoid the area if possible.
Major shipping associations and vessel owners are reacting:
The tanker association INTERTANKO confirmed that vessels received warnings and many shipping operators are suspending or delaying transit through the strait for “several days” amid the risk.
Maritime advisories from other governments (e.g., Greece) have also urged ships to avoid the Persian Gulf, Gulf of Oman, and Strait of Hormuz due to safety concerns tied to the conflict.
A U.S. Maritime Administration notice specifically encourages U.S.-flagged vessels to stay well clear of potential conflict zones and keep in close contact with naval coordination units.

Iran’s Islamic Revolutionary Guard Corps (IRGC) has been reported — via the EU naval mission and other maritime monitoring sources — to have broadcast radio messages on VHF saying that “no ship is allowed to pass the Strait of Hormuz.”
These warnings appear to be coming from Iranian military broadcasts (not an official legal closure order).
It is unclear whether these messages amount to a binding legal blockade under international law, and some maritime authorities (e.g., the UK’s maritime trade operations unit) note that VHF radio warnings are not themselves sufficient to constitute a formal closure.

Traffic has already slowed or reversed: Tanker tracking data shows some oil and LNG vessels are slowing down, turning back, or waiting outside the strait instead of transiting.
Insurance costs are rising, with war-risk policies being cancelled or increased sharply for ships in the region due to heightened danger.
The Strait of Hormuz remains legally open under international law, but commercial and naval advisories are effectively creating a de-facto avoidance zone around it because of the risk of military action or misidentification incidents.

About 20% of global oil and significant volumes of liquefied natural gas (especially from Qatar) normally transit the strait daily. Disruptions or delays in this shipping can have major impacts on global energy prices and supply chains.
The situation — with both Iran’s communications and the U.S./international warnings — has created a near-shutdown of regular tanker traffic, even without a legally declared blockade.

Whether labeled a “lockdown,” the current reality is this:

There is no universally recognized legal closure of the Strait of Hormuz.
Iran has broadcast warnings that ships should not transit, and many shipowners are heeding that advice.
The U.S. and other governments are warning or advising vessels to avoid the area because they cannot guarantee safety amid escalating strikes.
In practice, traffic is being suspended or rerouted, which has effectively throttled normal maritime navigation through this critical chokepoint.