Check: Make a Swim
check once per round while you are in the water. Success means you may swim at up to one-half your
speed (as a
full-round action) or at one-quarter your
speed (as a
move action). If you fail by 4 or less, you make no progress through the water. If you fail by 5 or more, you go underwater.
If you are underwater, either because you failed a Swim
check or because you are swimming underwater intentionally, you must hold your breath. You can hold your breath for a number of rounds equal to your Constitution score, but only if you do nothing other than take
move actions or
free actions. If you take a
standard action or a
full-round action (such as making an attack), the remainder of the duration for which you can hold your breath is reduced by 1 round. (Effectively, a character in combat can hold his or her breath only half as long as normal.) After that period of time, you must make a DC 10 Constitution
check every round to continue holding your breath. Each round, the DC for that
check increases by 1. If you fail the Constitution
check, you begin to drown.
A creature with a swim
speed can move through water at its indicated
speed without making Swim checks. It gains a +8 racial bonus on any Swim
check to
perform a
special action or avoid a hazard. The creature always can choose to take 10 on a Swim
check, even if distracted or endangered when swimming. Such a creature can use the
run action while swimming, provided that it swims in a straight line.