Middlesbrough will join Celtic, Cardiff City and Vitoria Guimaraes in contesting the Algarve Cup in July.
Gareth Southgate will see his side take on Scottish champions Celtic on 22 July and then Champions League-bound side Vitoria Guimaraes on the 24 July.
The organisation of the event means that Boro and FA Cup finalists Cardiff cannot meet in the tournament.
All four matches will take place at the Estadio Algarve, home of Portuguese side SC Farense near the city of Faro.
Meanwhile Middlesbrough have added Scottish Premier League side Hibernian to their pre-season fixtures list - they travel to Easter Road on Saturday 2 August.
BBC SPORT | Football | My Club | Middlesbrough | Boro join Celtic in Algarve Cup