The finals will feature sixteen national teams, as has been the format since 1996. Some European football associations were in favour of expanding the tournament to 24 teams, although the number of UEFA members had hardly increased since the last tournament extension in 1996 (53 in April 2006 compared to 48 for Euro 1996). In April 2007, UEFA's Executive Committee formally decided against an expansion for 2012.
Twelve of the sixteen finalists participated at the previous tournament in 2008, with England and Denmark returning having last participated in 2004. The Republic of Ireland return after an absence of 24 years to make their second appearance at a European finals. One of the co-hosts, Ukraine, make their debut as an independent nation, having previously won the inaugural competition in 1960 as part of the Soviet Union. Euro 2008 winners Spain have qualified to defend their title. They will compete to win an unprecedented third consecutive major tournament, having won both UEFA Euro 2008 and the 2010 FIFA World Cup. The sixteen finalists who will participate in the final tournament are:
- Czech Republic
- Republic of Ireland