Nautilus Shell is a rare aquatic treasure item added to Minecraft in Java Edition 1.13 and Bedrock Edition 1.4 during the Update Aquatic. Nautilus Shell cannot be crafted; players obtain Nautilus Shell by fishing in open water as a treasure catch, by trading 5 emeralds to a wandering trader, or as a drop from drowned that spawn holding one — roughly 8% of drowned in Java Edition and 3% in Bedrock Edition. The spiral shell texture mirrors a real nautilus, with a cream-and-brown banded pattern that stands out in the inventory.

Nautilus Shell exists for one purpose: crafting a Conduit. Eight Nautilus Shells arranged around a single Heart of the Sea create a Conduit, the underwater beacon that grants the Conduit Power effect for breathing, faster mining, and night vision below water. Because drowned and wandering traders restock, Nautilus Shell is a renewable resource, so an ocean base can eventually field several Conduits. Stock at least eight Nautilus Shells before building a guardian farm or monument raid platform, where Conduit Power keeps you mining without drowning.