The best place on the island for information and help getting a hotel room, boat tickets, car, or motorbike (and arranging hiking excursions) is Aegean Thesaurus Travel and Tourism, with offices on the port (tel. 22840/32-152; www.thesaurus.gr) and on the main square in Apollonia (tel. 22840/33-152). Aegean Thesaurus handles tickets for all hydrofoils and ferries. Check at either office to get the helpful information packet on Sifnos for 2€. Just off the main square in Apollonia, Xidis Travel (tel. 22840/32-373; www.xidis.com.gr) is another good travel agent.
Visitor services are centered in or just off the main square in Apollonia. This is where you will find the National Bank (tel. 22840/31-317), with an ATM; the post office (tel. 22840/31-329); the telephone office (OTE); the police (tel. 22840/31-210); for medical emergencies call tel. 22840/31-315. The municipal website www.sifnos.gr is useful.