RIYADH — Saudi Arabia and Iran agreed Friday to open a standing bilateral channel on Persian Gulf maritime security, in what officials in both capitals described as the first dedicated Riyadh-Tehran working group since the April 15 ceasefire and a discreet sequel to the donor conference that closed in Marseille on Thursday night.

The channel, formally titled the Saudi-Iranian Joint Coordination Mechanism on Maritime Affairs, will convene in alternating sessions in Muscat and a yet-to-be-named Gulf city beginning May 25, according to a joint communique released simultaneously by the Saudi foreign ministry and the Iranian foreign ministry shortly before noon local time. The two-paragraph text, the product of more than three weeks of Omani back-channel work, commits the parties to “regular technical consultations on commercial navigation, search and rescue, environmental incidents, and the deconfliction of national naval assets” in the Persian Gulf and the Strait of Hormuz.

The announcement caps a fortnight that has moved post-war diplomacy in the Gulf from declarations to plumbing. The Islamabad framework, agreed in mid-April, produced a ceasefire. The Doha framework, opened May 2, produced a process. The Geneva inspections accord, signed April 28 and operationalized in Tehran last Sunday with the reactivation of cameras at Natanz, produced verification. The Marseille pledging conference, which closed Thursday with $71.4 billion in headline commitments, produced money. Friday’s bilateral, the smallest in scope of the four, may matter as much as any of them, several diplomats argued, because it is the first to commit two of the war’s principal antagonists to talk to each other directly, on a recurring calendar, without a mediator at the table.

“The mediators wrote the architecture, but the architecture has to be lived in,” said Prince Faisal bin Farhan, the Saudi foreign minister, in a brief televised address in Riyadh. “We are now living in it. We will live in it carefully.”

Iranian Foreign Minister Abbas Araghchi, in remarks aired on state television from Tehran, called the channel “a sober and reciprocal arrangement that reflects the realities of geography and the obligations of neighbors.” He noted that Iran and Saudi Arabia had each maintained naval forces in the same body of water “for as long as either of our modern states has existed” and said that the absence of a working mechanism for routine deconfliction had been “anachronistic.” Araghchi made no reference to the broader Doha or Geneva tracks.

The mechanism, according to two Omani officials familiar with the preparatory exchanges who spoke on condition of anonymity, will operate at two tiers. A senior tier of foreign ministry and naval staff will meet quarterly to set policy and review incidents. A working tier of port authority, coast guard and Strait of Hormuz traffic-control officials will meet monthly to handle operational coordination. A hotline between the Royal Saudi Naval Forces’ Eastern Fleet headquarters at Jubail and the Islamic Republic of Iran Navy’s headquarters at Bandar Abbas, dormant since 2016, will be reactivated within thirty days.

The arrangement is markedly narrower than the multilateral escort regime endorsed in Marseille on Wednesday, which committed French, Italian, Spanish, Greek and Egyptian naval contributions to a thirty-six-month rotation in the Strait of Hormuz and Bab el-Mandeb. Saudi and Iranian officials said the bilateral was complementary rather than alternative, and that Riyadh in particular wanted both a multilateral umbrella underwritten by European navies and a direct line to Tehran for the incidents that would inevitably arise beneath that umbrella.

“You can have the European frigates in the Strait, and you should,” said John Reilly, a senior analyst at Citi’s geopolitical risk practice, in a telephone interview from London. “But when a Saudi-flagged tanker has a near miss with an Iranian fast boat at three in the morning off Bandar Lengeh, you do not want the resolution path to run through Paris. The Saudis have learned that lesson the hard way. So have the Iranians.”

The diplomatic mechanics behind the announcement traced back to the forty-minute encounter between Prince Faisal and Araghchi on the sidelines of Marseille on Wednesday afternoon, which French officials disclosed at the time but described as exploratory. According to a senior European diplomat involved in the conference, the two ministers used the meeting to validate language that Omani and Pakistani envoys had been drafting since late April, and instructed their teams to finalize the text overnight. Pakistani Foreign Minister Ishaq Dar, who shepherded the Islamabad framework, was briefed in Marseille on Thursday morning and signed off on the language, the diplomat said.

Oman’s role was again decisive. Foreign Minister Badr Albusaidi traveled to Tehran on April 24 and to Riyadh on April 30, carrying drafts in both directions. A senior Omani official, speaking on condition of anonymity to describe sensitive shuttle work, said the Iranian side had insisted on language that did not subordinate the bilateral to the broader Doha process and that the Saudi side had insisted on inclusion of the Strait of Hormuz, which Iranian negotiators initially wanted to address only in a separate annex. Both demands were accommodated in the final text.

In Washington, the State Department welcomed the announcement in measured terms. “Direct communication between Riyadh and Tehran on maritime safety is a constructive development,” spokesperson Matthew Miller said in a midday statement. “It is consistent with the regional architecture the administration has supported since the ceasefire.” A senior administration official, briefing reporters on the condition of anonymity, said the U.S. Fifth Fleet at Manama had been briefed in advance and would coordinate with both parties through existing channels. The official declined to say whether Washington had been shown the final text before its release.

Israeli reaction was cooler. A spokesman for Prime Minister Benjamin Netanyahu’s office said Israel would “judge regional initiatives by their effect on Israeli security, not by their press releases,” and reiterated that Jerusalem reserved the right to act against threats originating from Iranian-aligned forces regardless of bilateral mechanisms among other states. A senior Israeli official, speaking on condition of anonymity, said the government was nonetheless quietly relieved by the narrowness of the Saudi-Iranian text, which makes no mention of land borders, missile programs, or proxy forces.

The bilateral also drew a careful response from the United Arab Emirates and Qatar, both of which were given advance notice. Emirati Foreign Minister Sheikh Abdullah bin Zayed, in a statement from Abu Dhabi, called the channel “a welcome step within the broader Gulf framework” and noted that the UAE maintained its own bilateral lines with Tehran. Qatari Foreign Minister Mohammed bin Abdulrahman Al Thani, whose government hosted the April prisoner exchange and the May 2 framework talks, said Doha would support any mechanism that “reduced the distance between speeches and behavior.”

Beyond the immediate region, the bilateral was read as a signal about the pace of Saudi-Iranian normalization more broadly. The two countries restored diplomatic relations under Chinese mediation in 2023, but the relationship has remained brittle, and the war saw Saudi airspace used for U.S. and Israeli refueling operations and Saudi Patriot batteries intercepting Iranian and Houthi missiles. The Friday text does not address any of those legacies. It addresses ships.

“That is the discipline of the moment,” said Layla Hassan, a Beirut-based regional analyst with the Carnegie Middle East Center, in a telephone interview. “You do not try to solve the war by negotiating the war. You try to make the peace boring. Coast guard meetings, port authority calls, search-and-rescue drills. If they can sustain that for a year, they will have built something.”

The first session of the senior tier is scheduled for May 25 in Muscat, with the inaugural working tier session to follow in early June. Officials said additional bilateral tracks on environmental incidents and on civil aviation safety would be considered after the maritime mechanism had been tested. A joint Saudi-Iranian readout from Muscat is expected at the end of the May session, the two ministries said.