Sulfur Caves is a rare underground cave biome that generates at depths comparable to lush caves and dripstone caves. It forms only under specific noise conditions — low weirdness values at or below -0.85, combined with medium continentalness and high erosion — making it most common beneath flat terrain near swamps and deserts. Sulfur springs may emerge at the surface directly above the biome, acting as a visible indicator of Sulfur Caves below.
The cavern floors of Sulfur Caves are composed largely of sulfur and cinnabar blocks in roughly equal proportions, with deepslate and stone filling the gaps between them. Acid-green sulfur pools are scattered across the cavern floor, and potent sulfur blocks lining the bottoms of these pools release a noxious gas marked by bubble particles visible both within and above the water. Any mob or player that contacts this gas receives the Nausea effect. Sulfur spikes of varying sizes grow atop sulfur blocks throughout the biome, and mineable ores are scarce because sulfur and cinnabar displace most of the surrounding stone. The sky fog within Sulfur Caves takes on a distinctive green hue.
Sulfur cubes are the signature mob of Sulfur Caves, spawning in groups at the highest rate. Cave spiders, creepers, skeletons, zombies, endermen, zombie villagers, witches, and slimes in slime chunks also spawn here. Glow squids inhabit the sulfur pools in Bedrock Edition. Mineshaft chest minecarts that end up inside these caves may carry the Bounce music disc, so the biome is a good place to hunt for it.