What this campaign was
Launched in January 2025 after repeated damage to Baltic cables and pipelines, Baltic Sentry deploys frigates, patrol aircraft and naval drones and integrates national surveillance. It is the module's first standing activity against hybrid pressure, and it attributes no incident to anyone.
The Baltic Sea is enclosed by Allied and partner coastlines except at the Russian shores, and the electricity, gas and data links crossing it belong to civilian operators rather than to militaries. Baltic Sentry is how the Alliance put a military watch over civilian infrastructure without owning it, and it is the mechanism through which damage to a cable became an alliance matter rather than an operator's insurance claim.
Confidence: High As of 2026-09Reviewed 2026-09-21
Summary
NATO states that following several incidents involving critical undersea infrastructure in the Baltic Sea it launched the enhanced vigilance activity Baltic Sentry in January 2025, and that since then the activity has enhanced the security of that infrastructure by deploying a range of assets including frigates, maritime patrol aircraft and a fleet of naval drones. NATO says it is working with Allies to integrate national surveillance assets, improving the ability to detect threats to critical undersea infrastructure and respond if required. The activity is described as multi-domain and as a way of countering destabilising acts in the Baltic Sea. NATO later stated that Eastern Sentry builds on the experience of Baltic Sentry.
Stated objectives
What the participants say. Each entry cites where the position was stated; Vigil records that it was made, not that it is true.
To enhance the security of critical undersea infrastructure by deploying maritime and air assets and integrating national surveillance, improving the ability to detect threats and respond if required.
NATO's own description of the activity.
Assessed objectives
Vigil's reading, graded. Kept structurally apart from stated positions so an assessment can never be published as someone's declared aim.
Its deterrent logic is observation rather than protection: the seabed cannot be guarded along its length, so what the activity changes is the probability that a vessel's behaviour is watched, recorded and attributable at the time it occurs.
Primary forces
- Allied Maritime Command Primary force · Confidence: Moderate · as of 2026-09-21
Allied Maritime Command is NATO's maritime command and the parent of the standing naval forces; no source read assigns it a defined command role in this activity, and none is asserted.
Supporting & external
- Standing NATO Mine Countermeasures Group One Supporting force · Confidence: Low · as of 2026-09-21
A standing mine countermeasures group under Allied Maritime Command, recorded here because mine countermeasures is the capability nearest the seabed question. NATO does not publish which standing forces contribute to the activity, and no contribution is claimed.
Outcome and present status
Running since January 2025 and named by NATO in June 2026 as a current eastern-flank maritime activity. NATO states that Eastern Sentry builds on its experience, which makes it the template for the flank-wide activity that followed rather than a superseded arrangement.
Observed adaptations
NATO describes the integration of national surveillance assets as part of the activity rather than as a separate programme, which makes it a coordination mechanism over capabilities Allies already held as much as a deployment of new ones.
Political implications
It commits the Alliance to a continuous response to a class of incident whose attribution remains, in every case in this module, unresolved or contested — which is a political exposure as much as a military one.
Military implications
The activity is surveillance and presence, not protection of a line. Its military contribution is detection and the attribution of behaviour at the time it occurs.
Economic implications
The assets under watch are commercial: interconnectors, gas pipelines and telecommunications cables owned by operators, whose repair costs and outage consequences fall outside the alliance entirely.
Linked events
Locations
Places this module already publishes as map markers, listed because the campaign is about them. Not an operational area.
What remains unknown
- NATO publishes no participating units, vessel names, numbers or areas for the activity, and none is carried here.
- Whether the standing naval forces contribute to it is not published.
- No end date, review point or success criterion has been published.
Readings the evidence also supports
- The activity's launch can be read as a response to a campaign of sabotage, or as a response to a rise in accidental anchor damage in a crowded and shallow sea with an ageing shadow fleet crossing it. The public findings support both readings in different cases, and this module records the cases rather than choosing between the readings.
Listed because the record's own assessment is not the only one its sources permit — not as a hedge on the assessment above.
Whether any incident under the activity reaches state attribution
No occurrence in the module's undersea set has reached state attribution. The first that did would change what the activity is understood to be responding to.
Whether the activity's assets are published
NATO names asset classes — frigates, maritime patrol aircraft, naval drones — and not units or numbers. A published order of battle would be a change in NATO's own disclosure practice.
Watch questions this campaign bears on
Standing analytical questions whose evidence runs through this campaign, each with its latest review. Derived from the Watch object, never restated here.
See the force running this in Explore Interactive: select this record and follow what connects to it.
Assessed as of — 2026-09 Last reviewed — 2026-09-21