England failed to make the finals and the four winners of the League A groups will meet to find the second ever winner of the Nations League.
Group A1's winner is also the European champions Italy who won and drew three in the group stages and will now face the Group A4 winners, Spain.
Spain beat Germany to the top of the group after Man City's Ferran Torres scored a hattrick to thrash them 6-0 in the final group stage match in November.
Belgium won Group A2 and will face the Group A3 victors France, who are unbeaten in the competition.
Belgium were ranked as the best in the world according to the latest FIFA World rankings of the men's teams.
England failed to get second place in their group after losses against Belgium and Denmark.
UEFA Nations League finals: Fixtures
The first semi-final will be held on Wednesday, October 6 and Italy's clash with Spain will kick-off at 7:45pm UK time.
The second semi-final is on Thursday, October 7 as Belgium face France with the same kick-off time.
The final of the Nations League is then set to be played on Sunday, 10 October at 7:45pm. The third place play-off will be held on the same day at 2pm.
UEFA Nations League finals: Where is it?
All the finals will take place in Italy.
Italy v Spain will be held at the San Siro in Milan while Belgium v France is at the Juventus Stadium in Turin.
The third place play-off will also be in Turin while the final will take place in Milan.
The UEFA Executive Committee confirmed in December that Italy would hold the finals after three international associations in Group A1 were interested in hosting the European tournament.
UEFA Nations League finals: Will there be extra-time and penalties?
If the scores are level at the end of normal time, the traditional 30 minutes of extra time will take place followed by a penalty shoot-out if there still isn't a winner.
The third-place decider however, will not follow the same rules and if it ends in a draw, the tie will go straight to a penalty shoot-out.
What happened in UEFA Nations League 2019?
The inaugural Nations League competition was won by Cristiano Ronaldo's Portugal who won the final 1-0 against the Netherlands in convincing fashion.
Goncalo Guedes scored a fantastic goal in the second half to lead Portugal to win the cup in Porto in front of thousands of home fans.
The semi-final ended in dramatic style too as Portugal won 3-1 against Switzerland thanks to Ronaldo, who scored two late goals to squash Swiss hopes and in the process net a hattrick.
Netherlands reached the final by beating England 3-1 in the semis which took two extra-time goals to thwart the Three Lions, also in an action-packed match-up.
Marcus Rashford put England ahead through a penalty in the first-half before Matheus De Ligt scored a great header to equalise, but ultimately it was errors that lead to the Dutch victory.
Kyle Walker scored an own-goal just seven minutes into extra-time after a terrible passing blunder from John Stones.
To make matters worse Ross Barkley attempted back-pass was scuffed to gift Quincy Promes an open goal and to put the dreadful extra-time to bed.
After a brilliant conclusion to the first competition and then a dramatic Euro 2020, fans will be hoping to see more action-packed football over the next week.