The Marsh is considered the most dangerous and inhospitable of all biomes for its native Tentacles, which attack without provocation, and Merms which, while only hostile at close proximity, present a danger when camping in or near marsh areas. Spider Dens appear frequently in the Marsh, which normally leads to confrontation with other mobs. As a result, players can take away lots of loot after their wars end. This can also make it possible for a player to camp in a marsh if they are prepared and brave enough, though it's not easy: see the Marsh Camp Guide for more tips on how a player can survive this harsh biome.
It is recommended to keep moving and stay on the roads to avoid being attacked by the Marsh's hostile inhabitants. Tentacles cannot spawn on roads, which makes them useful when moving around. A player can find Reeds randomly scattered across the area, which can also rarely spawn outside of the Marsh Biome.
Marshes are also the only biome where Tentacles, Spiky Trees, and Spiky Bushes exist in the base game. In the Reign of Giants DLC, Spiky Trees and Spiky Bushes can also be found in the Desert Biome. Mermhouses also appear in marshes. While they can also be found outside of a marsh, this is very rare.
Spider Infested Cave Marshes
It is rich in Reeds and a player can harvest an average of fifty Cut Reeds in the whole area. However, this biome is also infested with Tentacles and at least five tier-three Spider Dens. Therefore, players should take extreme caution when venturing into this area.
It is possible to generate a world where no Marsh Biome exists in the Caves.
Light Flower Cave Marshes
It is less dangerous than the first one. This biome is abundant with Light Flowers and is inhabited by a Tentapillar. Sometimes, Tentacles can also be found in this area, but not as much as the first one.
In the Shipwrecked DLC, a different variant of Marsh Biome can be found, called Tidal Marsh. Tidal Marshes are entirely covered with Tidal Marsh Turf. This biome contains Reeds and Green Mushrooms similar to the original Marsh, as well as Tidal Pools replacing Ponds, and Flups replacing Tentacles. Additionally Fishermerm's Huts and Poisonous Holes can often be found in this biome. Unlike Tentacles, Flups are renewable, and over time new Flups will spawn in Tidal Marsh Turf tiles around the Marsh.
|Surface||Chess • Grasslands • Graveyard • Forest • Marsh • Mosaic • Rockyland • Savanna
(Desert • Deciduous Forest ) (Beach • Coral Reef • Jungle • Magma Field • Mangrove • Meadow • Ocean • Tidal Marsh • Volcano ) (Battlegrounds • Cultivated • Deep Rainforest • Gas Rainforest • Lily Pond • Pig City • Painted • Pinacle • Rainforest • Suburbs • Wild Plains ) (Lunar Forest • Lunar Mine • Rocky Beach • Waterlogged )
|Caves||Mushtree Forest • Rocky Plains • Stalagmite Terrain • Sunken Forest • Cave Swamps|
|Ruins||Labyrinth • Military • Sacred • Village • Wilds
|Related||Bridge • Map • Road (Trail) • Turfs • Abyss
(Interiors ) (Lunar Island )