The Karmsund Bridge, a part of the European route E134 highway, links Karmøy to the mainland.

The small islands of Vibrandsøy, Risøy, and Hasseløy lie in the strait at the northern end, just off shore from the town of Haugesund.

[1] Near the Norsk Hydro Factory on Karmøy, there are three powerlines that cross the Karmsund on 143-metre (469 ft) tall electricity pylons, which are the tallest in Norway.

[2] The eddic poem Grímnismál says that Thor, the weather god, wades the straits at Karmsund every morning on his way to Yggdrasil, the tree of life.

Standing above Karmsund, near Haugesund, is Haraldshaugen, a monument commemorating the traditional burial site for several early Norwegian rulers, including Harald I.