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The Marine Expeditionary Units: What They Are Built to Do

Two Marine Expeditionary Units sailed toward Iran in March 2026. Officials said sending them "does not mean" a ground operation. This page explains what these units are, why experts quoted in the Israeli press said only they could do the job being planned, and where they went.

What a MEU is​

A Marine Expeditionary Unit (MEU) is a Marine force of about 2,200 to 2,500 Marines that lives aboard three Navy amphibious ships. It carries its own infantry battalion, helicopters, MV-22 Osprey tilt-rotor aircraft, F-35 jets, landing craft, and supplies. It exists to put Marines ashore from the sea, fast, and to seize a beach, an airfield, an island, or an oil platform.

Marine veteran Jonathan Hackett told the Jerusalem Post on 15 March 2026: "Only the MEU can conduct this type of operation." He said the 31st MEU could launch a battalion landing team of up to 550 Marines ship-to-shore with its own air and logistics support, and could "seize and hold gas and oil platforms." Military historian Lynette Nusbacher told the same paper that "this Marine unit could be on its way to secure landing places for an air-delivered infantry brigade as part of a phased joint operation on Iranian soil" (Jerusalem Post, 15 March 2026). She added that without a very large mobilization, including reserve and National Guard forces, the United States would be unlikely to have enough troops on the ground to overthrow Iran's government.

The 31st MEU, from Japan​

  • 13 March: Hegseth approved a CENTCOM request to send the 31st MEU, permanently based in Japan, about 2,200 Marines on three ships led by the USS Tripoli, with F-35s and Ospreys (Times of Israel; Israel Hayom). The Times of Israel: "Trump officials had long ruled out the idea of sending ground troops to the region, but have largely avoided ruling out the possibility since the outbreak of the war."
  • 16 March: Israel's Channel 14, as relayed on X, reported that "the United States is planning potential ground operations," naming the 31st MEU.
  • 27 March: the Tripoli arrived in the CENTCOM region with about 3,500 sailors and Marines. Israel Hayom called it the "First US ground force" to arrive near Iran, "an advance force for ground capabilities the administration is reportedly trying to build" (Israel Hayom, 28 March 2026). The same day Iran's parliament speaker said Iran's forces were "waiting for American soldiers" (BBC).
  • 19 April: the 31st MEU seized the Iranian-flagged ship Touska at sea (Wikipedia, Touska).

The 11th MEU, from California​

  • 20 March: Reuters and the Wall Street Journal reported about 2,500 Marines of the 11th MEU and the USS Boxer group, with the Portland and Comstock, heading to the region "even as President Trump insists he won't put American boots on the ground in Iran" (Algemeiner / Reuters; FinancialJuice, citing the WSJ). The Jerusalem Post counted about 4,500 Marines and combat personnel on the Boxer's three ships (Jerusalem Post, 22 March 2026).
  • Israel Hayom, 30 March: the Boxer was carrying "about 4,000 Marines and sailors, including 2,500 Marines," which left San Diego on 20 March (Israel Hayom).

Together, CBS reported, "roughly 5,000 Marines" from the 11th and 31st MEUs were part of the Pentagon's ground preparations (see CBS, 20 March). Israel's Channel 13 counted about 7,500 Marines in the region within ten days under the Pentagon's plans (Channel 13).

"Not boots on the ground"​

The MEUs were the force for the island options: Kharg, Larak, Abu Musa (see Axios's "final blow"). Rep. Pete Sessions (R-Texas) said on CNN, as Politico and others reported: "I believe that what these 2,500 Marines would be is to secure the island. The island is not, in my opinion, boots on the ground in combat circumstances. It's not like inside Iran in the cities" (Politico, 17 March 2026). Fox's Brian Kilmeade said Marines on Iranian islands are "not really in Iran," as a Threads tag page recorded it.

Marines landing on an Iranian island from the sea, under Iranian missiles and drones, are soldiers on Iranian soil. Rep. Nancy Mace (R-S.C.), after a Pentagon briefing, reached for the comparison every Marine family knows: "Seven thousand Marines died on the black sands of Iwo Jima" (as reported by LBC, 27 March 2026).

Status: Jonathan Hackett is alive. Lynette Nusbacher is alive. Pete Sessions is alive. Nancy Mace is alive. Pete Hegseth is alive.

Sources​

Last Updated: 2026-09-26

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