AUKUS Bets on Robot Submarines: Inside the Three-Nation Push to Flood the Indo-Pacific With Underwater Drones

Defence ministers from the United States, United Kingdom, and Australia stood together at the Shangri-La Dialogue in Singapore on May 30, 2026, and announced the first concrete project under AUKUS Pillar II: a trilateral program to jointly develop uncrewed undersea vehicles, with initial deliveries beginning in 2027 [1][2]. UK Defence Secretary John Healey framed it in stark terms: "This is what modern defence looks like. We are announcing ground-breaking underwater capabilities that will keep Britain safe" [1].

The announcement marks a turning point for AUKUS. Five years after the partnership's creation in September 2021, Pillar II — the advanced-capabilities arm focused on emerging technologies — has been widely criticized for producing more PowerPoint slides than weapons systems [7]. The UUV program is meant to change that. But whether it can deliver fast enough to matter, given China's substantial head start in underwater autonomy, remains an open question.

What the Program Actually Involves

According to the official UK government fact sheet, the UUV project will follow a phased development strategy [3]. In the first phase, each nation will develop interchangeable national payloads — mission-specific equipment packages for sensors, navigation, and offensive capabilities — designed for different mission effects. The second phase will produce jointly developed trilateral payloads and next-generation enabling technologies [3].

The scope of intended capabilities is broad: anti-submarine warfare, anti-surface warfare, mine countermeasures, electronic warfare, seabed infrastructure protection, strike operations, surveillance and reconnaissance, and logistics [1][2]. Enabling systems will support UUV coordination with crewed and uncrewed platforms, using shared standards, trilateral operational concepts, and common control systems [3].

The vehicles themselves range in size and capability. Small UUVs — roughly six feet long — can be launched from submarine torpedo tubes. Extra-large autonomous underwater vehicles (XLAUVs), comparable in size to a school bus, can carry payloads over ranges exceeding 6,500 nautical miles and fit inside standard 40-foot shipping containers for transport [4].

Each nation brings an existing national program to the table. Australia's Ghost Shark XLAUV, built in partnership with Anduril, is designed for intelligence, surveillance, reconnaissance, and strike; a manufacturing facility is under construction [4]. The UK's Project CETUS, producing the XV Excalibur XLUUV demonstrator through MSubs, is focused on undersea demonstration capabilities [4]. The US has procured six Boeing Orca XLUUVs, with first delivery expected in mid-2025 [4].

The Money Question

The UK has committed £150 million (approximately $201 million) to the program [1]. Aggregate trilateral investment figures have not been publicly disclosed, and total costs will depend on the scope of production runs beyond initial development.

On the US side, the broader Pillar II budget provides some context. The President's FY2025 budget requested $79.8 million in research, development, test, and evaluation funds for AUKUS Pillar II — triple the FY2024 level of $26.6 million [5]. But analysts at the Australian Strategic Policy Institute (ASPI) have noted that Pillar II funding "is buried in existing Defence budget lines" and that "the exact amount of money and the pathways and timelines are uncertain" [6].

Source: Congressional Research Service

Data as of May 30, 2026CSV

A June 2025 analysis in War on the Rocks was blunter: after four years, Pillar II had produced "minimal concrete results" and lacked "marquee deliverables" [7]. Unlike Pillar I, which prompted Australia to create a 550-person Submarine Agency, Pillar II had no comparable organizational depth. Staff turnover in the UK Ministry of Defence team eroded institutional knowledge, the US AUKUS Senior Advisor position remained vacant, and no dedicated shared funding mechanism existed [7].

The UUV program is explicitly designed to answer that criticism. Whether it succeeds depends on whether governments match the announcement with sustained appropriations.

The Contractor Landscape

Three primary defense contractors are positioned to receive the lion's share of work. Anduril Industries, the Palmer Luckey-founded defense technology firm, leads Ghost Shark production in Australia and is scaling manufacturing across AUKUS bases [4]. Boeing Defense builds the Orca XLUUV for the US Navy [4]. MSubs, a smaller UK firm, produces the Excalibur demonstrator [4].

Specific contract values and projected job creation numbers for the new trilateral program have not been released. The broader AUKUS enterprise — dominated by Pillar I's nuclear submarine program — carries a reported commitment of nearly $368 billion across all three nations [8]. The UUV component, while far less expensive than nuclear submarines, draws from existing defense budget lines rather than fresh allocations, limiting visibility into its true economic footprint.

China's Head Start

The AUKUS UUV announcement arrives against a backdrop of rapid Chinese advancement in underwater autonomy. By multiple independent assessments, China operates the most extensive large UUV program of any nation, with at least eight distinct vehicle types either in the water or in advanced testing [9][10].

Source: Covert Shores / CSIS / Naval News

Data as of May 30, 2026CSV

China's program spans a range of sizes that no other country matches. At the smaller end, the UUV-300CB measures 11.5 meters (38 feet), weighs 50 tonnes, and can carry sea mines, deploy smaller UUVs, and — in its armed variant — fire lightweight torpedoes [11]. At the larger end, China has pioneered an entirely new category: the "extra-extra-large" UUV, or XXLUUV. At least two prototypes, approximately 45 meters (130 feet) long — more than twice the length of the US Boeing Orca — have been undergoing sea trials in the South China Sea [12].

Source: Newsweek / Covert Shores / Naval News

Data as of May 30, 2026CSV

The AJX-002, a torpedo-shaped multi-purpose XLUUV measuring 18–20 meters, is designed for reconnaissance, transport, and strike missions [9]. Retired Admiral Mark Montgomery has warned that these vehicles could travel "almost anywhere" within ten hours and could support mine-laying operations around Taiwan [9]. One defense analyst quoted by Newsweek assessed that "based on drones in the water, and efforts at defense shows, China is leading the world in this emerging technology" [11].

The scale disparity is stark. The US currently operates a single combat-oriented XLUUV platform (the Orca), while China pursues development "at incomparable scale, scope, and speed," according to naval analyst H.I. Sutton's Covert Shores database [10]. The AUKUS trilateral program is designed to close that gap through industrial collaboration, but whether pooling three nations' relatively modest programs can match the output of China's centralized defense-industrial complex is a question that remains unanswered by the announcement itself.

Legal Gray Zones

The deployment of autonomous undersea weapons near submarine cables and critical maritime infrastructure raises questions that existing international law does not cleanly resolve.

The United Nations Convention on the Law of the Sea (UNCLOS), the foundational legal framework for maritime activity, was written before autonomous vessels existed. Article 29 defines warships by four requirements: ship classification, external nationality markings, command by a commissioned officer, and a crew under regular armed forces discipline [13]. Uncrewed vehicles fit awkwardly within this framework.

Legal analysis published by the Center for International Maritime Security (CIMSEC) argues that unmanned systems can qualify as ships — UNCLOS lacks a definition that excludes them — and that physical crew presence is not mandatory under other maritime conventions such as SOLAS and COLREG [13]. Three operational models create different legal exposures: "human in the loop" (continuous remote control), "human on the loop" (automated operation with human monitoring and veto authority), and "human out of the loop" (full autonomy) [13]. Systems with human oversight can satisfy UNCLOS requirements; fully autonomous lethal systems create accountability gaps that international law has not resolved [13].

The broader question of lethal autonomous weapons systems (LAWS) governance remains, in the words of the American Society of International Law, "one of the most controversial subjects in international law" [14]. A 2025 UN resolution launched informal consultations among member states, but no binding treaty exists [14]. The International Committee of the Red Cross has proposed safeguards including limiting autonomous engagements, avoiding deployment near civilians, restricting targets to inherently military objectives, and preserving human control over mission parameters [15].

The AUKUS announcement itself does not specify which autonomy model the trilateral UUVs will use, nor does it reference specific rules of engagement or arms-control commitments. The official fact sheet describes "common control systems" and shared operational concepts [3], but whether that implies meaningful human oversight at the engagement level or merely supervisory coordination remains undefined.

Regional Reactions: A Coalition Question

The decision to develop this capability within the three-nation AUKUS framework, rather than a broader alliance, has produced a range of responses across the Indo-Pacific.

Japan has been broadly positive. Tokyo was invited to consult on Pillar II in November 2024, with an initial focus on maritime autonomous systems interoperability, and Japanese forces participated as observers in 2024 Maritime Big Play exercises [16]. South Korea has likewise been receptive; in October 2024, the Biden Administration and Seoul established a vice-ministerial defense science and technology executive committee to explore Pillar II cooperation [16]. The Philippines, facing daily Chinese pressure in the South China Sea, has been described as the region's "only strong AUKUS supporter," viewing the partnership as a useful addition to regional security architecture [16].

Indonesia's response has been markedly different. Jakarta expressed "deep concern over the continuing arms race and power projection in the region" and called on Australia to comply with its obligations under UNCLOS [17]. Indonesia is particularly sensitive about military vessels — crewed or otherwise — operating in or under its archipelagic waters.

China itself has been direct. Beijing has called AUKUS "dangerous" and warned that it risks triggering a regional arms race [18]. North Korea views the partnership as part of what Pyongyang calls a "multilayered ring of nuclear encirclement" and has accelerated its own naval modernization, including development of an 8,700-ton nuclear submarine, partly in response [19].

The exclusion of key partners from the technology-sharing arrangement creates a strategic tension: the program aims to strengthen deterrence across the Indo-Pacific, but the technology it produces is restricted to three anglophone nations. Whether Pillar II consultation mechanisms with Japan, South Korea, and others evolve into genuine capability-sharing arrangements will shape whether the program reinforces or fractures the broader coalition.

The Case Against

Critics of the program exist within the defense establishments and legislatures of all three participating nations. Their arguments cluster around three themes.

Cost-effectiveness. An April 2026 essay in the Australian policy journal Pearls and Irritations argued that AUKUS locks its members into "an inflexible, decades-long commitment" to expensive platforms that commanders will be reluctant to risk in combat: "A submarine that cannot be risked is not a deterrent. It is a shrine" [8]. The author argued that genuine resilience "comes from adaptability, diversity and strategic humility" — qualities that a program tied to three specific contractors and a rigid timeline may not deliver [8].

Organizational readiness. The War on the Rocks analysis described Pillar II as "a solution in search of a problem" that leads with technologies rather than strategic capability needs [7]. After four years, the priority areas expanded from four to eight without corresponding resource increases, creating what the authors called an "immense agenda" without the organizational depth to execute it [7]. ASPI analysts separately noted that companies face evaluation "through national processes, so projects often move on three tracks rather than one" [6].

Escalation risk. Admiral Samuel Paparo, then-commander of US Indo-Pacific Command, has acknowledged that unmanned systems alone cannot cover the 8,000-mile Pacific theater and that integrated approaches are required [4]. Critics extend this point to argue that deploying autonomous systems near contested waterways and submarine cables — infrastructure that carries 97% of intercontinental data traffic — lowers the threshold for undersea conflict by creating ambiguity about whether a damaged cable was cut by a drone, a fishing trawler, or an act of war.

The Case For

Proponents counter on each point. The UUV program's relatively low per-unit cost compared to nuclear submarines means that more vehicles can be deployed and lost without catastrophic strategic consequences — the opposite of the "shrine" critique. The program's phased approach, starting with national payloads before moving to joint development, is designed to produce usable capability within 12–18 months rather than the decades-long timeline of Pillar I [3].

Ukraine's successful use of naval drones against Russia's Black Sea Fleet has provided a real-world proof of concept that small, inexpensive autonomous vessels can achieve outsized effects against conventional naval forces [1]. The UK's Atlantic Bastion programme, announced in 2025 to combine autonomous vessels and AI with warships for subsea infrastructure protection, was explicitly described as "a direct response to a resurgence in Russian submarine and underwater activity" [1].

And the China comparison, while sobering, also underscores the urgency: if Beijing already operates the world's most extensive underwater drone fleet, the AUKUS nations argue they cannot afford to wait for a perfect program before fielding capabilities that exist today.

What Happens Next

The 2027 delivery target for initial UUV capability is ambitious but not impossible, given that national prototype programs — Ghost Shark, Orca, Excalibur — already exist. The harder question is whether trilateral integration, interoperable payloads, and shared control systems can be delivered on the same timeline, or whether the program will follow the trajectory of Pillar I's nuclear submarine effort, which has already slipped by years and faces budget overruns [8].

ASPI analysts have proposed concrete fixes: publishing a clear strategy with milestones, creating dedicated budget lines for near-term capability packages and supply-chain development, assigning named program leads with quarterly trials, releasing funds in tranches tied to milestones, and publishing quarterly scorecards [6]. Whether governments adopt these recommendations or continue to manage the program through opaque bureaucratic channels will determine whether the May 30 announcement becomes a turning point or another entry in a growing list of AUKUS promises.

The underwater drone race is already underway. The question is no longer whether to compete, but whether this particular vehicle — a three-nation partnership with uneven funding, unresolved legal questions, and a competitor with a multi-year head start — can get there in time.