Baltic Sentry Ten Months In: A look at what’s working, what isn’t, and what comes next

What Baltic Sentry looks like:

It’s a layered mission: surface ships, aircraft, uncrewed systems, and a mix of NATO and national intelligence.

Air and ISR

There’s been a steady drumbeat of maritime patrol flights. The UK, Germany, and the U.S. all contribute P-8 sorties, and the UK has added Rivet Joint signals-intelligence coverage. These assets give the mission reach that surface ships alone can’t provide.

Surface forcesShips from SNMG1 and SNMCMG1 rotate through the Baltic. Frigates, minehunters, and patrol vessels from multiple nations now maintain a near-constant presence, especially around the Gulf of Finland, Bornholm Strait, and the routes into the Danish Straits. Additionally, the USS Bulkeley joined Baltic Sentry in late September 2025, becoming the first U.S. warship to slot formally into the mission.

Uncrewed systems and seabed monitoringNATO publicly references a growing use of naval drones. Industry reporting regularly highlights Saab’s Sabertooth AUV/ROV as a proven Baltic inspection tool.

Baltic Sentry Ten Months In: A look at what’s working, what isn’t, and what comes nextC. Faraday | 23 November 2025

On 14 January 2025, NATO announced Operation Baltic Sentry in Helsinki, a standing mission to protect the thick web of power and data cables that run across the Baltic Sea. It was a direct response to the Estlink 2 cable damage on Christmas Day 2024 and the cluster of other Baltic cable incidents that followed. Investigators linked one of those events to the Eagle S, a Russia-linked “shadow fleet” tanker. That episode showed just how quickly Europe’s energy and digital lifelines can be disrupted with a single anchor drag.

Before Baltic Sentry, the region relied on national patrols and the occasional NATO exercise. BALTOPS helped, but it mainly focused on surface and air activity rather than sustained attention to what was happening along the seabed. The launch of Baltic Sentry shifted that model: instead of short bursts of activity, it created a continuous, multinational presence.

Ten months later, there’s enough open reporting to make a grounded assessment of what’s actually changed. Some of it is genuinely impressive. Some parts remain awkward. And a few gaps could be fixed with tools and data NATO already has, no new kit or expensive programmes required. However, one point worth repeating: NATO officials have said that no confirmed hostile attacks on Baltic undersea infrastructure have succeeded since the mission began. Accidents still happen, but deliberate sabotage appears to have stopped.

(https://www.csis.org/analysis/natos-role-protecting-critical-undersea-infrastructure, 2023)

Four Gaps Consistently Highlighted in Open Reporting

Gap	What Open Sources Say	Why It Happens
1. Shallow-water acoustic clutter	CMRE, EPC, and several NATO commentaries note high false-alarm rates in the Baltic’s shallow, noisy environment.	Ferry traffic, fishing activity, temperature layers, and biological noise all overlap in waters averaging 55 m depth.
2. Tracking AIS-dark / AIS-spoofing vessels	ECFR, EPC, and open SAR/AIS analysis show attribution remains slow and inconsistent in heavy traffic.	Requires fusing AIS, radar, SAR, and behavioural signatures; no single feed is sufficient.
3. Relay coverage for uncrewed systems	BALTOPS and NATO exercise reporting describe persistent coverage challenges despite strong performance from USVs.	USVs/AUVs need to navigate shipping lanes and fishing zones, and require recharge cycles, creating predictable gaps.
4. Data-fusion delays	PISM, Carnegie, and JRC highlight multi-hour delays in sharing raw acoustic or SIGINT data across borders. NATO acknowledges this openly.	Sovereignty and classification rules slow the release of national feeds into a shared operational picture.

Practical Improvements That Don’t Require New Technology

Improvement	What It Involves	Why It’s Feasible Now
1. Retrain classifiers on Baltic environmental data	Use HELCOM, Copernicus Marine, and national datasets to adapt acoustic/sonar classifiers to local conditions.	CMRE and other NATO labs have already shown that region-specific environmental training reduces false alarms. The method exists; it needs applying to the Baltic.
2. Integrate EMSA & HELCOM ship-noise libraries	Combine existing noise libraries and AIS analytics used nationally (Finland, Estonia, others) into a shared Baltic Sentry picture.	Data already collected; the barrier is classification and legal alignment, not technology.
3. Lease more long-endurance USVs	Supplement NATO platforms with commercial USVs (e.g., Saildrone, Liquid Robotics) that already operate with Allied navies.	Proven endurance and availability. Leasing is fast and avoids major procurement cycles.
4. Align national feeds via existing frameworks	Expand bilateral sharing and tap into JEF’s established grey-zone data-sharing arrangements.	JEF has already demonstrated rapid maritime data exchange; applying the same model to Baltic Sentry is a political choice.

All four improvements rely on existing tools, datasets, and frameworks, not new hardware or new funding lines.

The UK’s Role and the Mission’s Results

The UK has been one of the most consistent contributors to Baltic Sentry. Regular P-8 Poseidon and RC-135 Rivet Joint flights provide a large share of the long-range acoustic and signals-intelligence coverage. British analysts and officers are embedded across NATO maritime structures, and the UK leads the Nordic Warden effort under the JEF, now routinely used to flag suspicious “shadow-fleet” behaviour before it becomes a problem.

Taken together, these contributions make the UK an enabler, not just a participant. Smaller Baltic states plug into the ISR picture the UK helps build, not the other way around.

What Baltic Sentry Has Achieved

Across open sources, three effects consistently stand out:

1. Presence works.The continuous mix of ships, maritime patrol aircraft, and uncrewed systems has changed how high-risk vessels behave. AIS/SAR analysis shows altered routes and patterns, even if exact percentages aren’t published.

2. Visibility has improved.Tallinn, Northwood, and national operations centres are sharing more data than they did a year ago, not perfectly, but measurably better. The “good enough to act on” shared picture simply didn’t exist before January.

3. Deterrence without drama.NATO’s public line is unchanged: there have been no confirmed hostile attacks on Baltic undersea infrastructure since the mission began. Accidents continue, but deliberate sabotage appears to have stopped.

These outcomes don’t mean the mission is flawless, as shallow-water acoustic clutter, attribution delays, relay coverage gaps, and slow fusion remain stubborn challenges, structural features of the region, not signs of failure.

Looking Ahead to 2030

The most useful improvements don’t necessarily require new technology; environmental retraining of classifiers, better use of noise libraries, a slight uplift in long-endurance USVs, and reduced classification friction in data sharing would all yield visible gains by 2027–28.

By 2030, the Baltic Sentry model could be adapted to other vulnerable regions, such as the High North or the Black Sea, if political conditions align.

Baltic Sentry was built quickly using what Allies already had. It doesn’t need to be perfect. Its first 10 months show that when political will exists, NATO can adapt quickly. The next phase requires refinement, not reinvention.

Sources

(All open as of 23 November 2025)

• NATO Maritime Command releases, Jan–Nov 2025

• Reuters, AP, YLE, ERR coverage of the Estlink 2 incident

• European Commission / JRC subsea infrastructure reports

• EPC “Battle of the Baltic” (2024)

• ECFR, Carnegie Europe commentary on Baltic subsea security

• USNI News reporting on Baltic Sentry and P-8 deployments

• BALTOPS 2024–25 public documentation

• Saab material on Sabertooth AUV/ROV

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