Strait of Hormuz

On January 4, 2021, the South Korean chemical tanker, Hankuk Chemi, was seized by Islamic Revolutionary Guard Corps Navy (IRGCN) personnel on speedboats who boarded the vessel in the Strait of Hormuz. $7 billion in Iranian funds were frozen in South Korean banks at the time due to U.S. sanctions, which likely contributed to Iran’s seizure of the Hankuk Chemi. South Korea later deployed its Cheonghae anti-piracy unit to the Strait of Hormuz and dispatched a diplomatic delegation to Iran. The Hankuk Chemi was held by Iran for three months before being released on April 9, 2021, without South Korea releasing frozen Iranian funds.

Arabian Sea, off the coast of Oman

On July 29, 2021, the Israeli-linked oil tanker, Mercer Street, was unsuccessfully attacked by two Iranian suicide drones in the Arabian Sea, off the coast of Oman. On July 30, 2021, another Iranian suicide drone attack against the same vessel killed 2 crewmembers. The USS Ronald Reagan and USS Mitscher then escorted Mercer Street to port. A CENTCOM investigation of the debris from the drone found components known to be used in Iranian suicide drones.

Gulf of Oman, near the Strait of Hormuz

On August 4, 2021, the Emirati oil tanker, Asphalt Princess, was hijacked by suspected IRGCN gunmen in the Gulf of Oman, near the Strait of Hormuz. The gunmen took control of the vessel, steering it towards Iran, before the approach of U.S. and Omani warships led the gunmen to flee the ship. The ship’s crew reportedly sabotaged the engine to slow its progress towards Iran.

Gulf of Oman

On October 24, 2021, Iranian personnel used fast attack craft, a helicopter, and the Harth 55 (Shahid Nazeri) catamaran to seize the Vietnamese-flagged oil tanker, Sothys, in the Gulf of Oman. Two U.S. Navy destroyers and a U.S. Coast Guard Cutter responded to the situation but were unable to prevent the seizure. Iran seems to have arranged the incident in part to generate propaganda footage, as the U.S. claimed that Iran had engineered a “Hollywood production” to embarrass the United States. Iran claimed it was simply protecting the Sothys from U.S. attempts at seizing the vessel, which the U.S. denied. Iran released the Sothys roughly two weeks later, after taking all its oil cargo.

Gulf of Oman

In mid-November 2021, the USS Essex was harassed by an Iranian helicopter in the Gulf of Oman. The helicopter circled around the USS Essex three times, coming within 25 yards of the ship before leaving. Following the incident Pentagon Press Secretary John Kirby called the fly-by “unsafe” and “unprofessional.”

Persian Gulf, 22 nautical miles off the coast of Iran

On May 27, 2022, two Greek oil tankers, the Delta Poseidon and Prudent Warrior, were seized by the IRGCN in the Persian Gulf. Iranian helicopters deployed personnel onto the tankers and seized them. This was presumably in response to the April 19 seizure of the Iranian tanker Lana by Greek authorities, which had been violating U.S. sanctions on Iran. Greek officials negotiated with Iran, who released the ships six months later from the port of Bandar Abbas.

Strait of Hormuz

On June 20, 2022, the USS Sirocco and the USNS Choctaw County were harassed by three IRGCN fast attack craft in the Strait of Hormuz. One of the IRGCN vessels approached the Sirocco head-on, coming within 50 yards of collision with the ship. The U.S. ships issued warnings to the IRGCN vessels, which departed after about an hour.

Persian Gulf

On August 29, 2022, the IRGCN support ship Shahid Baziar attempted to seize a Saildrone Explorer unmanned surface vessel operated by the U.S. Navy’s 5th Fleet Task Force 59 in international waters in the Persian Gulf. The Baziar tried to tow the Explorer to Iranian waters, citing a supposed threat to international shipping lanes. The U.S. Navy pursued the Baziar with the USS Thunderbolt and a MH-60S Sea Hawk helicopter, prompting the Baziar to release the Saildrone after approximately four hours.

Red Sea

On September 1, 2022, an Iranian navy vessel, the Jamaran, seized two U.S. 5th Fleet Saildrone Explorers unmanned surface vehicles that were operating in international waters in the Red Sea. The Jamaran attempted to hide the drones under tarps but released them after 18 hours of negotiations with the United States Navy, which deployed two destroyers, the USS Nitze and USS Delbert D. Blacke, both of whom launched their MH-60R Sea Hawk helicopters. The drones were missing their cameras when released.

Gulf of Oman

On November 15, 2022, the Liberian-flagged, Israeli-linked tanker, Pacific Zircon, was attacked by an Iranian Shahed-136 suicide drone in the Gulf of Oman. The drone flew into the aft section of the Pacific Zircon and inflicted minor damage, prompting the USS The Sullivans, USS Chinook, HMS Lancaster, and a P-8A Poseidon maritime patrol aircraft to respond to the scene. HMS Lancaster offered assistance to the crew of the Pacific Zircon, while U.S. explosive ordnance technicians boarded the vessel, assessed the damage, and collected debris fragments. A later investigation of the evidence confirmed Iran’s connection to the attack.

Strait of Hormuz

On December 5, 2022, the crews of the USS Lewis B. Puller and USS The Sullivans were subject to an attempted blinding by an IRGCN patrol boat, which shined a spotlight at their bridges and crossed within 150 yards of the U.S. ships in the Strait of Hormuz. The U.S. ships used non-lethal lasers and warnings to deescalate the situation. The ships were then able to continue their transit.

Gulf of Oman, 44 nautical miles from Muscat, Oman

On February 25, 2021, the Israeli-owned vehicles carrier, MV Helios Ray, suffered explosions that reportedly punched holes in the ship's sides, suspected to be the result of Iranian limpet mines attached to the ship. There were no casualties and the Helios Ray subsequently docked in Dubai. Israeli Prime Minister Benjamin Netanyahu blamed Iran for the attack.

Arabian Sea, 300 nautical miles off the coasts of India and Oman

On February 10, 2023, the Israeli-owned oil tanker, Campo Square, was attacked and lightly damaged by at least one Iranian drone in the Arabian Sea.

Gulf of Oman

On April 27, 2023, Iranian naval forces seized the Marshall Islands-flagged, Chevron-chartered, oil tanker Advantage Sweet. Iran claims that the seizure was in response to a crash between the Advantage Sweet and an Iranian ship that led to Iranian crew members to go missing and get injured. The U.S. Navy stated that “Iran’s actions are contrary to international law and disruptive to regional security and stability.” The Advantage Sweet’s last known location was near the Iranian port of Bandar Abbas.

Strait of Hormuz

On May 3, 2023, the Panamanian-flagged Greek oil tanker Niovi was swarmed by a dozen IRGCN fast attack craft in the Strait of Hormuz. The IRGCN craft forced the Niovi to head into Iranian territorial waters. The U.S. 5th Fleet monitored the incident with a UAV.

Persian Gulf

Around May 9, 2023, Iran seized the Panamanian-flagged oil tanker Purity, claiming that it had a court order to seize the vessel as it was allegedly illegally rented to a foreign individual. Iranian media announced the seizure on May 12th, 2021, while signals from the ship’s automatic identification system confirmed it had been in an Iranian port since May 9, 2021.

Strait of Hormuz

On June 4, 2023, the merchant vessel Venture was harassed by three IRGCN fast attack craft in the Strait of Hormuz. After an hour, the U.S. Navy’s USS McFaul and a P-8 patrol aircraft, as well as the U.K.’s HMS Lancaster, responded to the incident, causing the fast attack craft to leave and allowing the Venture to continue its passage through the Strait.

Gulf of Oman

On July 5, 2023, the Marshall Islands-flagged oil tanker TRF Moss was nearly seized by an Iranian naval vessel in the Gulf of Oman. After receiving a distress call from the Moss, the U.S. Navy dispatched the guided missile destroyer USS McFaul, an MQ-9 Reaper drone, and a P-8 patrol aircraft to the location, prompting the Iranian vessel to depart. Three hours later, Iran attempted to seize the MT Richmond and again disengage once the McFaul arrived.

Gulf of Oman, 28 nautical miles northeast of Muscat

On July 5, 2023, just three hours after the attempted Iranian seizure of the TRF Moss, the MT Richmond Voyager was nearly captured by an Iranian vessel 28 nautical miles off the coast of Muscat, Oman. Iran claimed to have had a court order to seize the Richmond Voyager after it allegedly collided with an Iranian vessel. Iranian personnel fired multiple bursts from small arms and crew-served weapons at the Voyager prior to the arrival of U.S. forces. The Voyager sustained minor damage and no casualties. The U.S. Navy dispatched the guided missile destroyer USS McFaul, and the Iranian vessel subsequently retreated.

Arabian Sea

On March 24, 2021, the Israeli-owned container ship, Lori, was struck by a suspected Iranian missile in the Arabian Sea. The Lori sustained minor damage and no casualties. It continued to India after the attack. The same Israeli businessman who owned the previously attacked Helios Ray also owned the Lori. This attack came around two weeks after Iran claimed that Israel had damaged one of its container ships, the Shahr e Kord, in the Mediterranean Sea.

Southern Persian Gulf

On April 2, 2021, the USCGC Monomoy and the USCGC Wrangell were harassed by three IRGCN fast attack craft and a twin-hulled support vessel, the Harth 55 (Shahid Nazeri), in the Southern Persian Gulf (sometimes referred to as the Arabian Gulf). The Iranian vessels came within 70 yards of the U.S. fleet, repeatedly crossing in front of the American vessels. The crews of the two U.S. vessels issued warnings and maneuvered defensively until the Iranian vessels withdrew after approximately three hours.

Gulf of Oman, near Fujairah

On April 13, 2021, the Israeli-owned vehicles carrier, Hyperion Ray, was attacked by an Iranian missile in the Gulf of Oman, near the UAE’s port of Fujairah. The Hyperion Ray suffered minor damage and no casualties. The missile strike came a week after the Iranian vessel Saviz was damaged in a suspected Israeli mine attack. The Saviz was alleged to serve as a floating base for the Iranian Revolutionary Guard Corps (IRGC) in the Red Sea.

Persian Gulf

On April 26, 2021, the USS Firebolt and USCGC Baranoff were harassed by three IRGCN fast attack craft in the Persian Gulf, who came within 70 yards of the U.S. vessels. The U.S. vessels issued warnings and the USS Firebolt eventually fired warning shots, after which the Iranian vessels moved to a safe distance.

Strait of Hormuz

On May 10, 2021, six U.S. Navy and Coast Guard vessels and a U.S. Navy guided-missile submarine were harassed by thirteen IRGCN fast attack craft in the Strait of Hormuz. The U.S. ships issued warnings and the USCGC Maui eventually fired around 30 warning shots after two IRGCN craft approached to an unsafe distance, causing the IRGCN boats to disengage.

Northern Indian Ocean

On July 3, 2021, the container ship, CSAV Tyndall, previously owned by an Israeli-run shipping company, was attacked by an unknown weapon, suspected to be a drone or mine of Iranian origin, in the Northern Indian Ocean. The ship subsequently caught fire but sustained only minor damage and no casualties.

Gulf of Oman, near Sohar, Oman

In July 2021, shortly after setting sail from Sohar, Oman, the Guyana-flagged oil tanker Winsome was reportedly seized by Iran in the Gulf of Oman. The ship was missing for at least a month and was reportedly later anchored in the Iranian port city of Bandar Abbas next to the Sothys, a ship Iran had subsequently seized.