The UK Royal Air Force (RAF)'s Typhoon detachment deployed to Amari air base in Estonia will take part in Nato's Baltic Air Policing (BAP) mission until the end of August this year.
Four RAF jets will operate alongside pilots and engineers to secure Nato's airspace over the Baltic states of Estonia, Latvia and Lithuania.
The Typhoon fighters will launch a quick reaction alert (QRA) in response to any aggression from Russia, or others.
UK Defence Secretary Michael Fallon said: "This deployment underlines our commitment to the sovereignty of the democratic nations of Eastern Europe.
"24 hours a day, seven days a week for the next four months, our RAF Typhoons will be ready to respond instantly to Russian aggression in Baltic airspace."
The latest deployment marks the UK's third consecutive year of participating in the BAP, after rotations in 2014 and 2015.
During the last deployment, Typhoon fighters were scrambled 17 times, and intercepted over 40 Russian aircraft.
In July last year, the Typhoons intercepted ten Russian aircraft, including eight fighters.
140 Expeditionary Air Wing RAF commanding officer wing commander Gordon Melville said: "I am very proud to be leading 140 Expeditionary Air Wing as we again provide air policing support to our Estonian Nato allies.
"Although we are all far from our families and friends while over here, our hosts have given us a warm welcome and we are looking forward to working with them over the next four months.
Image: Typhoon aircraft arrive at Amari Air Base in Estonia prior to undertaking the Baltic Air Policing mission for Nato. Photo: courtesy of Crown Copyright.