Cruises Around the Fjord -- Båtservice Sightseeing, Rådhusbrygge 3, Rådhusplassen (tel. 23-35-68-90), offers a 50-minute boat tour. You'll see the harbor and the city, including the ancient fortress of Akershus and the islands in the inner part of the Oslofjord. Cruises depart from Pier 3 in front of the Oslo Rådhuset (City Hall). They run from mid-May to late August daily on the hour from 10am to 7pm during the high season, less frequently at the beginning and end of the season. Tickets are NOK120 ($24/£12) for adults, NOK60 ($12/£6) for children.
If you have more time, take a 2-hour summer cruise through the maze of islands and narrow sounds in the Oslofjord. From May to September, they leave daily at 10:30am and 1, 3:30, and 5:45pm; the cost is NOK210 ($42/£21) for adults, NOK105 ($21/£11) for children. Refreshments are available onboard.
City Tours -- H. M. Kristiansens Automobilbyrå, Hegdehaugsveien 4 (tel. 23-15-73-00), has been showing visitors around Oslo for more than a century. Both of their bus tours are offered daily year-round. The 3-hour "Oslo Highlights" tour is offered at 10:15am. It costs NOK300 ($60/£30) for adults, NOK150 ($30/£15) for children. The 2-hour "Oslo Panorama" tour costs NOK215 ($43/£22) for adults, NOK105 ($21/£11) for children. It departs at 10:15am. The starting point is in front of the Nationaltheatret. Arrive 15 minutes before departure; tours are conducted in English by trained guides.
Summer Evenings on the Oslofjord -- Summer evenings aboard a boat on the Oslofjord can be restful and exhilarating, but if you happen not to have a private yacht of your own, there are several outfitters who can solve your problem. The best of these is Båtservice Sightseeing AS, Rådhusbrygge 3 (City Hall Pier no. 3; tel. 23-35-68-90; www.boatsightseeing.com), which operates from a low-slung concrete building directly atop one of the piers adjacent to Oslo's City Hall. Between late June and the end of August, weather permitting, they operate nightly cruises that showcase, better than any other means of transportation, the intricate cays, skerries, sandbars, and rocks of the Oslofjord.
You'll travel aboard one of three historic sloops, each of which retains its pinewood masts and complicated 19th-century rigging. During the course of these excursions, you'll be moving by diesel-powered engines, not by wind power. The oldest and most oft-used of the three ships is the Johanna, a wood-sided sloop originally built in 1892. Passengers sit at plank-built tables on an open deck, retreating to a glassed-in cabin, or even below decks, if the weather turns foul.
Included in the price are heaping buckets of Norwegian shrimp, served buffet-style from a central table on deck, which you'll peel yourself, and which taste marvelous with the bread, butter, and mayonnaise provided by the cruise director. Beverages come from a cash bar (beer only), and entertainment derives from the vistas and panoramas that unfold on all sides. They include views of the hundreds of private summer homes, often inhabitable only 4 months a year, built alongside the Oslofjord. Departures are nightly at 7pm (late June-Aug only), with a return scheduled for 10pm. The price is NOK355 ($71/£36) per person. Significantly, most of the participants aboard these cruises are likely to be Norwegians, some of them from Oslo, who appreciate the chance for a firsthand view of the midsummer sea and its banks.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.