The coast is here thickly fringed with islands (the skargard), through which a main channel, the Saltsjo, penetrates from the open sea, which is nearly 40 m.
The skargard of the Cattegat, north of Varberg, is bald and rugged.
The islands of the skargard as a whole are rugged and picturesque, though never lofty like many of those off the Norwegian coast.
The numerous inland waters and sheltered channels within the skargard have caused the high development of sailing as a summer sport, the Royal Swedish Yacht Club having its headquarters in Stockholm.
The extensive system of natural waterways, especially in central Sweden, has been utilized to the full in the development of internal navigation, just as the calm waters within the skargard afford opportunity for safe and economical coastwise, traffic. The earliest construction of canals dates from the 15th century, the patriot Engelbrekt and King Gustavus Vasa both foreseeing its importance.
The sea-fisheries, which are prosecuted principally in the calm waters within the skargard, are a variable source of wealth.
Owing to the natural configuration of the coast and the skargard excellent natural harbours are almost without number.