Uefa says Euro 2028 joint-hosts England, Scotland, Wales and the Republic of Ireland will have to come through qualifying to participate in the competition.
Nine venues across the four home nations will stage the 24-team tournament.
Unlike previous Euros that have seen the hosts qualify automatically, Uefa has had to alter its protocols given the 2028 edition is being held across the four nations.
Instead, 20 nations will go through, with 12 as group winners and eight as the best-placed runners-up.
Two of the remaining four spots will be allocated to the two best-ranked host nations who did not qualify automatically, while the final two places will be decided via play-offs for the remaining runners-up in the group phase.