The Spanish Air Force (SAF) took over NATO's rotating Baltic Air Policing mission at Ämari on Wednesday, replacing the UK's RAF which has been patrolling the skies for the last few months.
This will be the SAF's third stint in Estonia since 2014 and it has returned with Eurofighter Typhoons, twin-engine fighter jets built as a joint project by Germany, Italy, Spain, and Great Britain.
The patrol is on call 24/7 and carries out reconnaissance and training flights when necessary.
Baltic airspace is guarded by the mission as Estonia, Latvia, and Lithuania do not have their own fighter jets.
The scheme started in 2004 in Lithuania, soon after the three countries joined NATO, and expanded to Estonia in 2014.
The Italian Air Force is currently based at Šiauliai Air Base in Lithuania.
Spain's NASAMS air defense system is also currently stationed in Estonia and training to "smoothly transition from air security to an air defense posture", said Kusti Salm, permanent secretary of the Ministry of Defense, in a statement.
At last month's summit in Vilnius NATO allies agreed on a new defense strategy for the eastern flank.
Editor: Helen Wright