From the Arctic Circle to the shores of the Baltic, a series of largescale military activities will demonstrate the unity, power and reach of partner nations defending peace and security in northern Europe.
TARASSIS is the most ambitious live activity of the Joint Expeditionary Force (JEF) since it was established at the NATO 2014 Summit in Wales, as a regional security cooperation structure for participating nations.
Activities begin in early September and run until the end of October, involving thousands of troops, sailors and aircrew, and dozens of ships and aircraft operating across the North Atlantic, Scandinavia and the Baltic Sea Region.
TARASSIS brings together a series of military activities to demonstrate the ability of the JEF to act collectively and project power in response to a threat to regional security. TARASSIS will also demonstrate how the JEF complements NATO deterrence and reassurance activities in peacetime and crisis.
Truly multi-national and multi-domain, TARASSIS will incorporate activities in the Land, Sea, Air, Space and Cyber domains. As well as JEF nations, Canadian forces will participate in TARASSIS. Interaction with NATO exercises will also showcase the JEF’s ability both to act independently and to complement the Alliance.
The UK acts as the Framework Nation to the JEF, so TARASSIS will be coordinated from the UK’s Standing Joint Force Headquarters (SJFHQ) near London.
HQ spokesperson, Group Captain Jonathan Eastlake Royal Air Force, said: “TARASSIS represents a significant step forward in our collective ability to respond rapidly and decisively to emerging threats. These exercises are not only about military preparedness—they are about unity, deterrence, and demonstrating our shared commitment to regional stability.”
He added: “By planning, executing, and communicating military activities across all domains, the JEF is making a significant contribution to European and Transatlantic security”.
TARASSIS activities are designed around scenarios that reflect real-world challenges in different domains. These events will be used to rehearse a series of prepared response options that can be quickly activated to deliver effects such as protecting an airfield, patrolling a sea lane or reinforcing a JEF nation.
TARASSIS is a long-standing commitment in the JEF calendar, marking the beginning of a regular, three-yearly cycle of JEF activities designed to build on the capabilities and interoperability of JEF nations.
Key activities and dates:
- BALTIC EXPRESS: The theatre entry of a UK strategic Roll on-Roll-off ship to reinforce Baltic nations (1-7 September)
- Ex EASTERN SEA: A series of anti-submarine and sea-lane protection exercises involving JEF nation maritime forces in the Baltic Sea (10 September to 14 October)
- Ex PROTECTIVE FENCE: Finnish Air Force-led live-fly air exercise to demonstrate defence capability and readiness in Finland (22 to 26 September)
- Ex NAMEJS: UK staff support the command post phase of Latvia’s major annual national defence exercise (30 September-8 October)
- Ex FOREST GUARDIAN and AUSTERE SHIELD: Deployment of UK land forces to demonstrate the ability to reinforce and support Latvian armed forces with theatre enablement and point defence of key facilities (20 September-20 October)
- ARCTIC TIDE: Amphibious operation to demonstrate UK-Norway ability to deploy freely, protect and resupply its forces anywhere in northern Europe (1-11 October)
- Distinguished Visitors day: An opportunity for key decision-makers and representatives from JEF nations to gather in London to demonstrate unity and showcase JEF capability. (14 October)
TARASSIS:
Objectives
- To demonstrate readiness and interoperability of JEF nations to reinforce each other
- To refine JEF Response Option plans
- To deter malign activity in the JEF Area of Interest (High North, Scandinavia, North Atlantic, Baltic Sea Region)