Amed's underwater landscape formed 1.3 million years ago when Mount Seraya's lava flows met the Bali Sea, creating a jagged volcanic substrate that now anchors East Bali's densest coral assemblages. The coastline's seven consecutive dive sites — Jemeluk Bay, Lipah Beach, Selang, Banyuning, Amed Beach proper, Bunutan, and Aas — stretch eleven kilometres along the Karangasem regency and support over three hundred identified hard and soft coral species. A 1963 eruption from nearby Mount Agung deposited mineral-rich sediment that accelerated reef growth, establishing the conditions for present-day biodiversity. What distinguishes an Amed snorkeling tour from Bali's southern beaches is bathymetric simplicity. Shallow fringing reefs begin five metres from shore and descend gradually, keeping vibrant coral heads and resident fish populations within two to eight metres of the surface throughout the day. The Japanese patrol boat sunk during World War II rests at twelve metres in Banyuning, its hull encrusted with table corals and frequented by schools of fusiliers and occasional Napoleon wrasse. Jemeluk Bay's underwater temple installation — a stone garden shrine placed at four metres in 2005 — has become a nursery site for juvenile angelfish and damselfish, its carved pedestals wrapped in orange soft coral. Traditional jukung outrigger boats remain the standard transport for multi-site itineraries, their narrow hulls drawing less than thirty centimetres and allowing operators to anchor within swimming distance of shallow reef zones. Morning departures between seven and ten capture peak visibility before midday wind fetch stirs sediment. The Lipah Beach wall drops from three metres to thirty across a twenty-metre span, creating thermal layers where pelagic species — tuna, barracuda, mola mola during July and August — drift past stationary snorkelers. Conservation fees collected at beach entry points fund mooring buoys that prevent anchor damage to live coral.