Spain initially proposed eleven stadiums, while Morocco works on preparing its own facilities as part of the joint bid. Reality quickly imposed itself. On the Spanish side, La Coruña and Málaga have already withdrawn, and some warn this won't be the last withdrawal.
The Spanish federation believes FIFA will cut the number of stadiums in both Spain and Morocco. Of the nine that remain on the Spanish side, at least two or three are expected to fall away. The same logic applies to Morocco, where the list of proposed facilities may be reviewed against identical criteria.
Relatively confirmed among the Spanish grounds are the Santiago Bernabéu, Camp Nou, Metropolitano and San Mamés. In Morocco, the host cities face similar challenges over capacity, technical standards and surrounding infrastructure.
Take Spain's Anoeta stadium. Its capacity sits right at the maximum threshold FIFA require, a situation that may well repeat itself in some Moroccan grounds that need substantial upgrades.
Antón Meana, a journalist at Spain's "Cadena SER" radio, reckons Vigo's chances don't look strong, while Valencia enjoy better prospects. Reaching eight stadiums in total, he adds, would count as an achievement.
That anticipated reduction means Moroccan cities may also lose opportunities they had been banking on, especially those that invested in initial planning without final guarantees.
Both countries share the challenge. FIFA demand strict standards covering transport, hotels and security zones, so cities that can't meet them quickly, whether in Spain or Morocco, face the choice of withdrawal or the risk of exclusion.
All of which leaves the two nations needing precise coordination to present a balanced bid, one that preserves the spirit of joint hosting without loading either party with unjustified burdens.