Shark Fin Reef

Shark Fin Reef runs like a half-submerged spine, its exposed crest suggesting the fin that named it, with two long faces of tilted granite slab sliding into sand past 30 m. The eastern side stacks hard-coral gardens and sweeping slab scenery; the west goes steeper and moodier. Blue-spotted ribbontail rays shuffle under ledges, garden eels stipple the deep sand, titan triggerfish excavate with their usual self-importance, and this southern corner remains one of the archipelago's better bets for a zebra shark flat out on the bottom. An unflashy, spacious dive that shows the Similans' scale without demanding anything exotic in return.

您此行的高光时刻: Kilometer-scale granite spine, rays and garden eels on the sand, southern-sector calm

地形地貌: Tilted granite slabs and coral gardens dropping to sand

水流: Flow runs the length of the ridge and the dive becomes a one-way drift along whichever face is in the lee.

入水方式: A long granite ridge southeast of island 3, its crest breaking the surface; often the first dive of northbound itineraries.

危险因素: Length of the ridge can string groups out in current; agree on the drift plan before rolling.

保育: Park rules apply; give nesting titan triggerfish their cone of territory in the warm months.

高氧（Nitrox）: 在此值得使用——各潜点深度落在富氧空气（nitrox）能有效延长免减压时间的区间（前提是持有相应认证）。