November to April is the ideal season to visit Kradan Island, which was declared a national park on October 14, 1981, along with the other islands around Trang. From May to October Kradan Island comes under the influence of the southwest monsoon. Trang's logistic position at the edge of the Andaman Sea means that it becomes the receiving end of strong winds and big waves during the monsoon season. This is a blessing in disguise to marine life; undisturbed by tourists, it gets a chance to replenish itself.