Buried Treasure Finder
Edition
Version
Seed
On Java a buried treasure chest is always at block 9, 9 of its chunk, buried in a beach. The map gives you those coordinates — dig straight down.
Always a Heart of the Sea, the item that makes a conduit, plus iron, gold and often a few diamonds.
On Java Edition, type /seed in chat (it needs cheats on, or operator rights on a server). On Bedrock, open the world's settings: the seed is listed under Game.