Swimming caps

A swim cap consisting of a synthetic rubber dome comprising a front portion, a top portion, a lower peripheral edge, and a rear portion between the lower peripheral edge and the top portion, the lower peripheral edge when the dome is worn having an opening into an interior head space disposed within and enclosed by the dome, a center of the rear portion having a single hole through and completely surrounded b the synthetic rubber, the hole communicating the interior head space with the outside, the hole is provided with an elasticized band around a circumference of the hole and positioned in the rear portion between the lower peripheral edge and the top portion and configured to, when the cap is worn, allow passing and exiting of within the interior head space through the hole and permit the hair to egress out of the dome and form a ponytail that hangs outside of the swim cap to thereby in use alleviate at least some cranial pressure the swim cap would otherwise apply.