up to 24 hours before the experience starts (local time)
Right next to Dinga restaurant, under the cave church "St. Archangel Michael." Look for a sign that says: SUP Rental and Tours. The sign is located near a tiny, neatly kept beach. So, if you'd be entering the village, the sign and the beach would be to your left.
You can cancel up to 24 hours in advance of the experience for a full refund.