Mountain bikers will find plenty of trails on which to keep themselves occupied in the Oslo hinterland. The tourist office has free cycling maps, with Sykkelkart Oslo tracing the bicycle lanes and paths throughout the city, and Idrett og friluftsliv i Oslo covering the Oslo hinterland. It also has a pamphlet called Opplevelsesturer i Marka, which contains six possible cycling and/or hiking itineraries within reach of Oslo.

Two especially nice rides within the city, which are also suitable to do on an Oslo City Bike, are along the Akerselva up to Lake Maridal (Maridalsvannet; 11km), and in the woods around Bygdøy. The trip to Maridal passes several waterfalls and a number of converted factories at the edge of Grünerløkka and crosses several of Oslo's more unique bridges, including the Anker, or eventyr (fairy-tale), bridge. Cyclists should be sure to stop for coffee and a waffle at Hønse-Louisas Hus. This can also be done on foot by taking the T-bane to Kjesås and following the path back into the city. Cycling, or walking, around Bygdøy is far more pastoral and provides ample opportunity for swimming breaks. There is a bike rack in front of the Norwegian Folk Museum. For more serious cycling, take T-bane line 1 to Frognerseteren and head into the Nordmarka.

A network of 1200km of trails leads into Nordmarka from Frognerseteren (at the end of T-bane line 1), including a good trail down to Sognsvann lake, 6km northwest of the centre at the end of T-bane line 5. If you're walking in August, be sure to take a container for blueberries, and a swimsuit to cool off in the lake (bathing is allowed in all the woodland lakes around Oslo except Maridalsvannet and Skjersjøen lakes, which are drinking reservoirs). The pleasant walk around Sognsvann itself takes around an hour, or for a more extended trip, try hiking to the cabin at Ullevålseter, a pleasant old farmhouse that serves waffles and coffee. The return trip (about 11km) takes around three hours.

The Ekeberg woods to the southeast of the city centre is another nice place for a stroll. During summer weekends it's a popular spot for riding competitions and cricket matches, and there's an Iron Age heritage path through the woods. To get to the woods, take bus 34 or 46 from Jernbanetorget to Ekeberg Camping. For a piece of architectural history, don't miss the Ekeberg Restaurant, one of the earliest examples of functionalism. On the way down, stop at the Valhall Curve to see the view that inspired Edvard Munch to paint The Scream.

When (or perhaps, if) the weather heats up, there are a few reasonable beaches within striking distance of central Oslo. Ferries to half a dozen islands in the Oslofjord region leave from Vippetangen Quay, southeast of Akershus Fortress. Boats to Hovedøya and Langøyene are relatively frequent in summer (running at least hourly), while other islands are served less often. The last ferry leaves Vippetangen at 6.45pm in winter and 9.05pm in summer.

The southwestern shore of otherwise rocky Hovedøya, the nearest island to the mainland, is popular with sunbathers. The island is ringed with walking paths to old cannon emplacements and the 12th-century Cistercian monastery ruins.

South of Hovedøya lies the undeveloped island of Langøyene, which has superb swimming from rocky or sandy beaches (one on the southeastern shore is designated for nude bathing). Boat 94 will get you there, but it only runs during the summer.