Cool Diving Resort is a PADI dive shop and guesthouse on Green Island (Ludao), Taitung, Taiwan, home to the world's deepest underwater mailbox where visitors can post a postcard from the reef. The center offers Discover Scuba Diving for guests without a certification (one-on-one instructor, full equipment and underwater photos), the full PADI course path from Open Water and Advanced Open Water through Enriched Air Nitrox, a combined AOW+Nitrox package, and a combined EFR/Rescue Diver course, all including course materials, equipment and Fubon liability/water-recreation insurance. Fun dives for certified divers are available as boat, shore or night dives, priced per group size, and the shop rents full scuba equipment, dive computers and torches by the day. Cool Diving can also arrange return ferry tickets to Green Island, scooter rental and dorm or double-room accommodation, including multi-day Discover Diving stay packages.