The walk along the river Akerselva is one of my favorite walking paths in Oslo. The rivers starts at the lake Maridalsvannet, flow down to the city centre and then into the fjord next to the Opera house. The total walk from Maridalen to the city centre is around eight kilometres, but you can start the walk at any point along the river to adapt the length of your walk.
Earlier, the river used to give power to factories, workshops and mills. Nowadays it is an important green lung in the city which offers opportunities for walking, biking, running and relaxing. In the upper parts of the river you will find several places to swim, and all along the river there are nice, green parks for picnics and fun with family and friends. You will also find opportunities to stop by cafés and galleries close to the river.
Several of my favourite spots are situated along Akerselva. At Frysja you can have a swim during summer. The city waterfall Møllefossen is beautiful during all seasons, and close by is the summer café Månefisken. Further down you can visit the Sunday market at Blå every weekend.
If you want to start at Maridalen, take bus no. 54 from the city centre and exit at Frysja.