Swimming skill
Swimming is the survival skill that measures your ability to move through bodies of water under your own power. Large, rushing rivers like the Jantspyre or the Faldesu require a fair or large amount of skill to cross safely, while more placid waters such as the Arthe Dale swimming hole are much less challenging. Still others are little more than large puddles that only get your feet wet (e.g. the little brook you wade through on your way to and from Wolf Clan). Generally, the strength of the water's current and its depth determine how difficult it is to swim in a certain area. Before taking the plunge, these can be estimated by using the command APPRAISE <direction> to study the waters in the direction you wish to travel.
Your success in swimming in a particular body of water depends on several factors. Besides swimming skill, your strength, stamina, encumbrance, and injuries play a role. Note that in earlier years swimming while encumbered would increase your learning while swimming, but this is no longer the case.
Places to Swim
Thanks to Simu and DRWiki accountholder Nikpack for the list (Oh The Places You Will Go)