Using a shovel enchanted with Fortune on sand in an ocean or river biome has a chance to yield sunken treasure. This can include rare loot like sponges and a Message in a Bottle.

Guide

In order to have a chance of obtaining a sunken treasure reward from a block of sand, the player must have at least 4 blocks of water above them and break the sand block with a shovel enchanted with Fortune. Each additional level of Fortune increases the chance of receiving sunken treasure from a sand block; Fortune I yields a 10% chance, Fortune II yields a 26% chance, and Fortune III yields a 48% chance.

Rewards

If the player obtains sunken treasure from a sand block, the distribution of items they can find is below. Note that the weights of the first table are not quite exact due to a simplification of how the sunken treasure loot tables are actually set up, but for all intensive purposes, they are close enough.

In Java Edition, each sunken treasure contains 1 item stacks, with the following distribution:

Item Stack Size [FN 1] Weight [FN 2] Chance [FN 3] Avg.
per chest
[FN 4]
Avg. # chests
to search
[FN 5]
 Bone 11729999917.3%0.1735.8
 Seagrass 11729999917.3%0.1735.8
 Mossy Cobblestone 11152999911.5%0.1158.7
File:ParallelItemSprite message-in-a-bottle.pngMessage In A Bottle 11152999911.5%0.1158.7
 Kelp 186499998.6%0.08611.6
 Prismarine Crystals 157699995.8%0.05817.4
 Prismarine Shard 157699995.8%0.05817.4
 Sea Pickle 157699995.8%0.05817.4
File:ParallelItemSprite waders.pngWaders 130099993.0%0.03033.3
 Bottle o' Enchanting 128899992.9%0.02934.7
 Scute 128899992.9%0.02934.7
 Gold Ingot 128899992.9%0.02934.7
 Leather Boots 125099992.5%0.02540.0
 Wet Sponge 117399991.7%0.01757.8
File:ParallelItemSprite treasure-chest.pngTreasure Chest 15899990.6%0.006172.4
  1. The size of stacks (or for unstackable items, number) of this item on any given roll.
  2. The weight of this item relative to other items in the pool.
  3. The odds of finding any of this item in a single chest.
  4. The number of items expected per chest, averaged over a large number of chests.
  5. The average number of chests the player should expect to search to find any of this item.