Reykjanesbær has for a long time been a legendary sports-town and there a three sports clubs operating in the town, Íþróttabandalag Reykjanesbæjar (Sports clubs association), http://irb.is/, Keflavík, íþrótta- og ungmennafélag (sports and youth club) , http://www.keflavik.is/ and Ungmennafélag Njarðvíkur (youth association), http://www.umfn.is/.

The sports clubs offer a wide variety of sports which the inhabitants can participate in. Such as football (soccer), basket ball, handball, swimming, judo, athletics, dancing, ballet, volleyball, taekwondo and jiu jitsu.

The website Sumar í Reykjanesbæ (Summer in Reykjanesbær) provides information regarding which recreational and sports activities are available for children during the summer months in Reykjanesbær. It changes to Vetur í Reykjanesbæ (Vinter in Reykjanesbær) in the wintertime. The urls, https://sumar.rnb is and https://vetur.rnb.is are both working all year around. 

Reykjanesbær operates two public swimming centres Waterworld (Sundmiðstöðin/Vatnaveröld) is located on Sunnubraut. It has a 50 meters inndoor pool, a 25 meter outdoor pool, hot tubs and a sauna. There is a 12.5 meter indoor pool in Njarðvík, two hot tubs and a sauna. Children up to 10 years of age get free swimming accompanied by a parent, or a legal guardian. Information about opening hours and prices can be accessed on http://sundlaug.is/reykjanes-sundlaugar and https://www.facebook.com/sundmidstodin.is/

There is a number of gym clubs and fitness centres operated in Reykjanesbær. Here are some of them: Sporthúsið, http://reykjanes.sporthusid.is/, Lífsstíll, http://www.lifsstill.net/, Sport 4 You, http://sport4you.is/ and Óm setrið, http://www.omsetrid.is/.

There are two golf clubs operated in the vicinity of Reykjanesbær, Golfklúbbur Suðurnesja at Hólmsvöllur golf course, see http://gs.is and Golfklúbbur Sandgerðis at Kirkjubólsvöllur golf course, see http://gsgolf.is.

Reykjanesbæ has a great variety of recreational activities for children and youth of all ages, such as KFUM (YMCA) and KFUK (YWCA), https://www.kfum.is/kfum-og-kfuk-a-sudurnesjum/, scouts, http://skatamal.is/heidabuar/, young peoples division Klettur at the Björgunarsveitinni Suðurnes Rescue Team, http://www.bjsudurnes.is/ , Brynballett , http://www.bryn.is and Danskompaní (dancing company), http://danskompani.is/.

Reykjanesbær has the community centre Fjörheimar operated for young people in classes 8 - 10 located at Hafnargata 88. The emphasis is placed on promoting a positive and healthy lifestyle of young people by offering a substance free and safe environment. The web of Fjörheimar is at http://fjorheimar.is/.
The same building has the 88 House, which is a young people‘s house, for those aged 16-25 years of age. There is a participation with other young peoples houses, and cooperation with the Fjölbrautaskóli Suðurnesja student association. The website of 88 House is at https://www.88.is/.