Getting to Ruhnu takes planning. In summer, small aircraft operate from Pärnu (about 30 minutes) on a scheduled service — there are a few flights per week, not daily, and the schedule varies by season. Check the Transaviabaltika website for current timetables; booking well in advance is advisable since the planes are small and seats fill.
By boat, the summer ferry service from Pärnu takes around three and a half hours and runs infrequently — typically once or twice a week. The crossing can be rough in poor weather. In winter, when the Gulf of Riga freezes, the island can be reached by ice road, but this is unreliable.
Ruhnu has no car rental, no taxis, and limited infrastructure. Bring everything you might need: the one guesthouse on the island should be booked far in advance. Most visitors arrive for a day trip on the plane, which allows just enough time to see the churches, the lighthouse, and the village.