Oslo is a relatively small city and parking is at a premium so a car is a bit of a liability. Fortunately, there is an extensive and superbly efficient public transport system involving buses, trams, subway, trains, and ferries.
The city is served by 50 bus lines and eight tram routes, all starting from Jerbanetorvet at Oslo S Station. The subway is called the Oslo T-Bane and there are five underground lines covering the city. All public transport runs from 5.30am to midnight, with tickets available from bus drivers or vending machines at stations.
The Tourist Ticket allows for unlimited use within 24 hours, while the 1, 2, and 3-day Oslo Pass allows unlimited travel on any form of public transport, and includes free museum admissions and other discounts. Ferries operate on a seasonal basis, between April and September, linking the City Hall to the museum-studded peninsula of Bygdøy. There are also ferry services to the harbour islands.
Metered taxis are easy to come by and can be found at ranks near shopping centres, city squares, stations and other gathering points. Cabs can also be ordered by telephone from a central office, or from taxi ranks. Ride-hailing apps like Lyft are available. Much of the city is compact enough to explore on foot.