Swimming The Styx

Warlock Invocation, Transmutation
Level: Least, 2nd lv.
Components: V, S
Casting Time: 1 standard action
Range: Self
Duration: 24 hours
Saving Throw: None
Spell Resistance: No

You channel the power of the infernal river, and become an aquatic creature

Effect: You become an Aquatic creature and gain a Swim Speed equal to you base land speed and all benefits derieved from having a natural swim speed In addition you gain the ability to breath water as well as air.

A creature with a swim speed can move through water at its swim speed without making Swim checks. It has a +8 racial bonus on any Swim check it makes to perform some special action or avoid a hazard. The creature always can choose to take 10 on a Swim check, even if rushed, distracted, or endangered or when swimming in stormy water. The creature can use the run action while swimming, provided it swims in a straight line. It also can charge, withdraw, or take a 5-foot step. Unlike creatures using the Swim skill, a creature with a swim speed does not have to make a Swim check each hour to avoid nonlethal damage.

[p. 124 Complete Mage]