Swim is a action for Graham.
To Swim is a special Action ability used by Graham in KQ1AGI and KQ2. Swimming is automatic for Gwydion and Rosella in KQ3 and KQ4, and is used to much extent. In KQ1SCI swimming is automatic for Graham (functioning much like swimming in KQ4). There are a few locations however where manual 'swim' command still works in KQ1SCI and in KQ4, but it functions a bit differently.
In KQ1AGI and KQ2, 'Swim' is accessed by typing 'swim', using the '=' key, or accessed through the Action menu.
Swimming also appears in KQ7 briefly in one of Valanice's chapters but this is largely within a cutscene, and is not under the player's control.
Attempting to swim in KQ5 or KQ6, will result in death scenes. You can swim on the edge of beach in KQ5 (but moving out to sea will lead to death). Swimming is impossible in KQ6, as undertows will grab Alexander and pull him out to sea the moment he loses his footing (or stops walking and attempts to swim).
Swimming in lakes, ponds, some rivers and oceans Edit
There are various bodies of water that often requiring swimming across or at least slow down the player's movement as they trudge through it. How they physically portrayed evolves over the series.
In the original King's Quest and King's Quest 2, Graham automatically goes into his struggle/drowning animation, and the player has to manually make the character swim. The water is always considered deep. If the player falls of a cliff into the water they automatically die from the fall/drowning. After a while of struggling they sink under the water and die. If swimming he holds up much longer while being in the water, but will get tired and struggle and drown after longer amount of time passes. Rivers in the games are almost always deadly.
In King's Quest 1 remake lakes come in different depths some Graham can walk through, only going up to his thighs, others go up his waist and others up this chest. He may still stand up and walk through many of these lakes. If its one of the higher lakes he can remain standing and walking through but comes up to his lower chest, he maybe able to start swimming by typing the 'swim' command. If the water gets any deeper than that he may automatically start swimming in the water. If he remains in the water swimming for a few minutes he does get tired and goes into a struggling/drowning animation.
In KQ4 the swimming functions similarly to the KQ1 remake, as Rosella has some water that she can walk through, and others that are deeper and come to her waist. In some of these 'swim' command might make her go from standing to swimming while in the water. More often than not in both of these games it might indicate that the water is too shallow for swimming. Most of the time however if the water is deep such as the ocean Rosella will automatically swim. In this game there are mostly no deadly water areas other than the swamp where Rosella will die in quicksand below the water. She can also get tired and drown anywhere she can swim.
In KQ5 other than the first screen of the ocean near the beach, Graham doesn't have many chances to swim. There is a rivers in Serenia Forest but these are deadly, and oasises and Willow's salt pond are shallow. Graham automatically swims when he enters the ocean, but grows tired if you leave the screen.
IN KQ8 Connor is not able to swim, and all lakes and water ways including the swamp are shallow enough to stand in. Their may only be one instance that Connor's movement through water might even be compared to swimming and that's traveling the whirlpools between the swamp and the Underground Realm of the Gnomes.
Behind the scenesEdit
Swimming as as an action was to be included in KQ8, but was cut in the later builds of the game. While there are areas of water, Connor walks slowly through it (similar to how characters walked in shallow water in earlier games). There is however one or two areas where Connor can drown or be killed by water in KQ8 (including the swift water near the waterfall, or the mill wheel, or the River of Death). Connor is sucked into and swims through a portal between the Swamp and the Undergroudn Realm of the gnomes but this is automatic, and split up via a loading screen.
Graham doesn't appear to know how to swim in the new King's Quest game, but its unknown if he'll learn how to swim in later episodes or if swimming mechanic will be left out entirely to avoid extra animations and programming. It appears even the swimming sequence in the Ancient Well has been removed from the KQ1 related prologue story.