1. Oslo Metro (T-Bane): The efficient and extensive metro system is the most convenient way to explore Oslo and its surroundings.

2. Trams (Trikk): Trams are a great option for traveling within the city center, covering major tourist attractions and providing scenic routes.

3. Buses (Buss): Oslo has a well-connected bus network that reaches areas not served by the metro or tram lines and is a good option for getting around the city.

4. Ferries (Båt): Taking a ferry ride is a unique way to experience Oslo, especially when visiting popular attractions like the Oslo Opera House or the museums on Bygdøy peninsula.

5. Oslo Pass: Consider purchasing the Oslo Pass, which grants you unlimited access to public transportation, including metro, tram, buses, and certain ferries, along with free admission to many museums and attractions.

6. Ruter Billett app: Download the Ruter Billett app to easily purchase and validate tickets for all modes of public transportation in Oslo, making your travel experience more convenient.