Rusa deer swim here. Each dry season a few cross nearly two kilometres of open strait from mainland Bali to graze on Pulau Menjangan, and the island carries their name: menjangan is the old Javanese word for deer. Nobody lives on its 175 hectares of limestone and dry savannah. The Dutch colonial administration first protected the surrounding coast as a nature reserve in 1941. The area was later gazetted as Taman Nasional Bali Barat, West Bali National Park, covering roughly 190 square kilometres of land and sea. Geography does the rest. Java's bulk deflects the southwest monsoon swell, and the mountains of the Bali hinterland cast a rain shadow that keeps this corner of Buleleng the driest in the province. The result is water that stays glassy for most of the year, with visibility commonly between 20 and 40 metres. Menjangan Snorkeling Trip & Diving tours work a fringing reef that begins in ankle-deep sand, shelves across a coral garden, then falls away as a near-vertical wall past 60 metres. Fewer than seven kilometres of coastline hold more than twenty named sites. Those sites read like a catalogue of reef architecture. Eel Garden runs sand chimneys full of garden eels. Pos I and Pos II stack gorgonian sea fans and barrel sponges along the drop-off. Bat Cave hides a low overhang beneath the cliff. The Anker Wreck, a wooden-hulled trading vessel of uncertain Dutch-era origin, lies canted between six and forty-five metres, its timbers now furred with black coral. Hawksbill turtles, bumphead parrotfish and whitetip reef sharks patrol the deeper ledges. Above the eastern shore, Pura Segara Giri Dharma Kencana and a cliff-top Ganesha shrine mark the island as sacred ground as much as a dive site. Conservation here is recent and deliberate. Thirty minutes east along the same coast, Pemuteran's Karang Lestari project has grown coral on low-voltage steel frames since 2000, one of the largest reef restoration efforts in the world and the reason local boat crews talk about this reef in decades rather than seasons. That ethic funds the park itself. Menjangan Snorkeling Trip & Diving tickets carry a 200,000 IDR conservation fee, per person, per weekday, rising to 300,000 IDR on weekends and holidays, levied by the national park rather than by any operator. The gate on the water opens at 06:00 and closes at 18:00, every day of the week. This is managed water, not open water, and it shows.