Óbidos is about 85 km north of Lisbon, an easy hour by car or a 75-minute ride on the Rede Expressos coach (multiple departures daily from Sete Rios station). There is also a regional train but the line is slow and the station is below the town, a stiff uphill walk to the gate.
Drivers should park in the large car park outside the southern walls — driving inside the town is not permitted for visitors and the lanes are too narrow anyway.