Difficult Terrain in Combat

Difficult terrain makes movement harder, costing extra movement to traverse.

Core rule: Every foot of movement in difficult terrain costs 1 extra foot of movement. Effectively, moving 1 foot costs 2 feet of your speed.

Stacking: Difficult terrain does not stack with itself. Multiple sources of difficult terrain in the same space don't make it cost 3 feet per foot — it stays at 2 feet per foot.

Common sources in combat:

• Rubble, debris, furniture, or bodies on the ground
• Spells: entangle, grease, spike growth, plant growth, sleet storm, web
• Natural terrain: thick undergrowth, shallow water, ice, steep slopes, deep snow
• Creature abilities: certain lair actions and legendary actions create difficult terrain

Movement types affected: Difficult terrain affects all ground movement including walking, crawling, climbing (without a climb speed), and swimming (without a swim speed). It does not affect flying movement unless the DM rules that the terrain extends upward.

Features that ignore difficult terrain:

• Ranger's Natural Explorer (in favored terrain)
• Druid's Land's Stride (level 6, nonmagical difficult terrain)
• Monk's Unarmored Movement (level 9, move on vertical surfaces and water)
• Freedom of Movement spell
• Any feature that says "you ignore difficult terrain"

Spike Growth interaction: Spike growth creates difficult terrain that also deals 2d4 piercing damage per 5 feet of movement through it. Because difficult terrain halves speed, creatures spend more time in the area and potentially take more damage if forced to move through it.