Croatia → San Marino: Short-stay tourist

You likely don't need a visa

You don't need a visa to visit San Marino as a tourist. San Marino's Foreign Ministry says that to reach the country you must cross the Schengen area, so visitors from outside Schengen need the authorisations required to enter and transit it, in practice, a Schengen visa where your nationality needs one. Your nationality doesn't need a Schengen visa, so a valid passport is what applies (EU/EEA citizens can also use a valid national ID card). San Marino's own pages don't list which nationalities need a Schengen visa, so this follows the EU's Schengen visa-free list, which can carry conditions, such as needing a biometric passport, or registering under systems like ETIAS once it is live, so confirm with an embassy or consulate of a Schengen state before booking non-refundable travel. San Marino's own law only requires a residence or stay permit if you plan to stay more than 30 days (see the checklist).

Source: Segreteria di Stato per gli Affari Esteri, Repubblica di San Marino