Naantali is fifteen minutes west of Turku by bus. Bus line 110 runs frequently from Turku city centre and from the Turku ferry terminal, making it straightforward to combine a day trip to Naantali with arrival by ferry from Stockholm or Tallinn. There is no train service to Naantali.
The nearest airport is Turku Airport, about twenty minutes away by taxi or local bus. Helsinki-Vantaa is a two-hour bus or train journey to Turku, from where you connect to Naantali. Most visitors travelling from elsewhere in Finland arrive via Turku.
Driving from Turku takes about fifteen minutes on highway 40. Parking is available near the harbour and the old town, though in high summer it fills up quickly. A car is not necessary if you are based in the town centre — everything in Naantali is walkable once you arrive.