How to Get Nautilus Shells in Minecraft

Guide Java Bedrock

Quick answer: Drowned holding a shell always drop it: 3% of drowned spawn with one in Java, 8% in Bedrock. You can also fish shells as treasure (up to 1.9% per catch with Luck of the Sea III) or buy them from wandering traders for 5 emeralds.

What you need

Weapon for drowned (Looting helps other drops)
Fishing rod (Luck of the Sea III ideal)
5 emeralds per shell at the wandering trader
Heart of the sea for the conduit

Step by step

Hunt shell-carrying drowned: drowned spawn in rivers, oceans and underwater caves. In Java 3% spawn with a nautilus shell in their off-hand, in Bedrock 8% - and that shell is a guaranteed drop. Bedrock zombie-to-drowned conversions count too.
Build a drowned farm: a river or ocean farm that funnels drowned to a kill spot produces shells automatically - the classic source for conduit projects.
Fish for them: nautilus shells are a fishing treasure: 0.8% per catch with no enchant, 1.9% with Luck of the Sea III. Fish in open water (since 1.16, treasure requires open water).
Buy them: wandering traders sometimes sell 1 nautilus shell for 5 emeralds. In Bedrock, a trader killed while offering a shell has a 25% chance (+1% per Looting level) to drop it if you're holding an emerald.
Try the 26.x nautilus: nautiluses themselves rarely drop shells when killed in current versions.
Craft the conduit: 8 nautilus shells around a heart of the sea. You need all 8, so a drowned farm or a fishing session is usually the real bottleneck of the conduit.
Bedrock bonus: a nautilus shell is one of the few items you can hold in your off-hand in Bedrock - pure decoration, but stylish.

Java vs Bedrock

The big gap is the drowned spawn rate with shells: 8% in Bedrock versus 3% in Java, making Bedrock drowned farms far better. Bedrock also lets zombie conversions carry shells and allows shells in the off-hand. Fishing odds and the wandering trader trade are the same.

Versions: Nautilus shells were added in Java Edition 1.13 (Update Aquatic, 18w15a) and Bedrock 1.4.0. Wandering trader sales came in 1.14, and the open-water fishing requirement in 1.16.

Frequently asked questions

What drops nautilus shells?

Drowned that spawn holding one (3% Java, 8% Bedrock) always drop it. Shells also come from fishing treasure (0.8-1.9%), wandering traders (5 emeralds), and rarely from nautiluses in 26.x versions.

How many nautilus shells do you need for a conduit?

Exactly 8, arranged in a ring around a heart of the sea. It's the hardest part of the conduit recipe - a drowned farm or Luck of the Sea III fishing rod is the way to go.

What is the fastest way to farm nautilus shells?

A drowned farm in a river or ocean: drowned spawn, get funneled to a kill chamber, and shell-carriers drop their shell every time. In Bedrock the 8% carry rate makes these farms twice as productive as Java.

Can you get nautilus shells without the ocean?

Yes: drowned spawn in rivers and in flooded caves, fishing works in any open water, and wandering traders come to you. No ocean biome strictly required.