Swim tops having a friction locking cord adjustment system are described. The swim top may have a pair of friction locking adjustment terminal ends. Each friction locking adjustment terminal end may be secured to an end of one of a pair of neck cords of the swim top. The friction locking adjustment terminal ends may be slidably affixed to the opposing neck cord of the swim top to permit the fit of the top to be adjusted. The friction locking adjustment terminal ends may be comprised of adjustment buckles or slidable knots. Adjustment buckles may include two or more silicone coated pads having holes for threading the cords of the swim top. A friction enhancing pattern may be proximate to the holes of the adjustment buckles. The friction enhancing pattern may engage the cord passing through that hole when the swim top is worn to enhance the secure fit of the swim top.