Underwater Combat
Underwater combat imposes disadvantage on most attacks, auto-miss on long-range shots, and grants fire resistance. Includes breath-holding and swimming rules.
Special rules apply when fighting in an aquatic environment.
Melee Attacks
A creature that doesn't have a swimming speed has disadvantage on melee weapon attack rolls unless the weapon is a dagger, javelin, shortsword, spear, or trident.
Ranged Attacks
- Ranged weapon attacks automatically miss targets beyond the weapon's normal range
- Even within normal range, the attack roll has disadvantage unless the weapon is a crossbow, net, or a weapon that is thrown like a javelin (spear, trident, dart)
Fire Resistance
Creatures and objects fully immersed in water have resistance to fire damage.
Breathing
A creature can hold its breath for a number of minutes equal to 1 + its CON modifier (minimum 30 seconds). When out of breath, a creature survives for a number of rounds equal to its CON modifier (minimum 1 round). At the start of its next turn after that, it drops to 0 HP and is dying.
Swimming
Each foot of movement while swimming costs 1 extra foot (2 extra in difficult terrain) unless a creature has a swimming speed. The DM may call for STR (Athletics) checks in rough water.