Cześć Kedziorek
This is the English forum so next time, please ask your question in English or head to our Polish forum

To answer your question - online poker in San Marino is regulated, however not in the same way as in Italy (it's more on the theoretical side rather than practical). This means that the San Marino players are not restricted to the .it player pool. For PokerStars it will be the .eu client.
(Odpowiedź w skrócie: .eu)