The UK and US are seeking technologies to defend ships, harbors, and other critical maritime infrastructure against the growing threat of underwater drones, and they are inviting industry to propose solutions.

The request comes as the US deploys uncrewed drone boats near Iran amid rising tensions. Iran is also believed to be behind at least two explosive-laden sea drone attacks on oil tankers in the Gulf since the US and Israel struck Iran on February 28. One attack reportedly occurred on March 1 about 44 nautical miles off Oman, and another on March 5 damaged a Bahamas-flagged crude tanker near Iraq’s Khor Al Zubair port.

Iran is already known to possess and use autonomous underwater vehicles in conflict. In 2024, it was seen sending torpedo-like drones and “one-way attack” underwater drones to Houthi forces in Yemen. Though small, these weapons are considered capable of causing serious damage to ships.

The UK Ministry of Defence said the US Defense Innovation Unit has launched a competition under a program called REEF, or Robotic Exclusion and Engagement Framework. The scheme is run jointly by the US and UK, and companies of all sizes can submit technologies directly for evaluation. American and British teams will review the proposals, while UK submissions will also be assessed by jHub, the innovation arm of the MoD’s Cyber & Specialist Operations Command.