If you're a student currently enrolled in classes then you can access the facility for no charge.
If you are not an enrolled student, then you'll need to either purchase a Campus Recreation Membership OR a one-time Campus Recreation pass (day, week, month). The Membership Pricing page can tell you all about costs, refunds and other FAQ's.
Once you have your membership, you are welcome to attend Lap Swim Hours during any sessions of the day; Morning, Noon, Evening.