"In a depression in amongst the dead coral lie a dozen ogre-like creatures with fins. One keeps watch while it's exhausted companions rest."
Updated Underwater encounters using D&D 2024 Monster Manual. Also a D&D 2014 version. Tables for Underwater Encounters (levels 1-4, 5-10, 11+), Beasts, Monsters and Spirits.
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Underwater Encounters
Encounters underwater bring visions of murky seas, vast reefs and dark depths. They might occur in a kelp bed, an underwater cave or by a long-forgotten shipwreck.
A totally different place to the surface, it is dominated by maelstroms and currents with vast tracks of open water. It is home to and reptilian sea races, tentacles beasts and primordial ancients
Underwater Encounter Tables - creatures (2014) | creatures (2024) | locations | non-combat | enhancements
A Note on Water Breathing
To expand options some stats and creatures are adapted from other environments. These may need a way of water breathing to survive underwater.
The water breathing spell lasts for 24 hours or several magic items grant water breathing, including cap of water breathing, cloak of the manta ray, necklace of adaptation and ring of water elemental command
Lastly, any creature can be made aquatic by giving it a swim speed equal to its walking speed and the amphibious ability.
Amphibious. This creature can breathe air and water
Underwater Levels 1-4
MotM = Monsters of the Multiverse
| 1d8+1d12 | Underwater Levels 1-4 |
|---|---|
| 2 | 1 giant shark or 1 kraken priest (MotM) |
| 3 | 1d4 lacedons or 1 sea hag with 1d2 sea spawn (MotM) |
| 4 | 1d4 sahuagin warriors and 1 sahuagin priest or roll on Sahuagin lvl 1-4 |
| 5 | 2d6 giant crabs or roll on Beasts |
| 6 | 1d2 chuul or roll on Monsters lvl 1-4 |
| 7 | 1d4+1 reef sharks or roll on Beasts |
| 8 | 1d3 sahuagin warriors and 1d3 reef sharks or roll on Sahuagin lvl 1-4 |
| 9 | 1d3 giant octopi or roll on Beasts |
| 10 | 1d2 merrow or roll on Monsters lvl 1-4 |
| 11 | 2d6 giant seahorses or roll on Beasts |
| 12 | 2d6 merfolk skirmishers or roll on Humanoids |
| 13 | 1d3 killer whales or 3d6 dolphins (MotM) |
| 14 | 2d4 steam mephits or roll on Spirits lvl 1-4 |
| 15 | 1d3 hunter sharks or 1d4 sea spawn (MotM) |
| 16 | 2d4 merfolk skirmishers & 2d4 giant seahorses or roll on Humanoids |
| 17 | 1d3 swarms of piranhas or 1 deep scion (MotM) |
| 18 | 1 sea hag and 1d2 swarms of piranhas or roll on Spirits lvl 1-4 |
| 19 | 1 archelon or 1d3 plesiosauruses |
| 20 | 1 water elemental or 1 sea elf spirit (banshee) |
Underwater Levels 5-10
| 1d8+1d12 | Underwater Levels 5-10 |
|---|---|
| 2 | 1 storm giant or 1 morkoth (MotM) |
| 3 | 1d3+1 giant sharks or 2d4 dolphin delighters (MotM) |
| 4 | 3d6 sahuagin warriors & 1 sahuagin baron or roll on Sahuagin lvl 5-10 |
| 5 | 1d4+1 giant constrictor snakes or 1 hydroloth (MotM) |
| 6 | A coven of 3 sea hags or roll on Spirits lvl 5-10 |
| 7 | 1d6 archelons or 1 water-breathing mage (replace fireball with vitriolic sphere) and 1 elemental water myrmidon (MotM) |
| 8 | 1d4 water elementals or roll on Spirits lvl 5-10 |
| 9 | 1d2 merfolk wavebenders with 3d6 merfolk skirmishers |
| 10 | 2d6 sahuagin warriors and 1 giant shark or roll on Sahuagin lvl 5-10 |
| 11 | Roll on Underwater Encs lvl 1-4; or 3d6 sea spawn (MotM) |
| 12 | 1d4+2 killer whales or 2d6 hunter sharks |
| 13 | 1d3 giant squids or roll on Monsters lvl 5-10 |
| 14 | 1d4+1 chuuls or 1 merfolk gladiator & 1d4 dolphin delighters (MotM) |
| 15 | 1 sea troll (swim 30 ft.) with 1d6 merrow or roll on Monsters lvl 5-10 |
| 16 | 2d6 plesiosauruses or 1 kraken priest (MotM) and 2d6 lacedons |
| 17 | 1d2 hydras or roll on Monsters lvl 5-10 |
| 18 | 1 sea hag and 2d4 merrow or 1 merfolk wavebender & 1d4 archelons |
| 19 | 1 marid or 1 kraken priest (MotM) and 1d6 deep scions (MotM) |
| 20 | 1 young black dragon or 1 aboleth |
Underwater Levels 11+
| 1d8+1d12 | Underwater Levels 11+ |
|---|---|
| 2 | 1 empyrean or 1 leviathan (MotM) |
| 3 | 1 animal lord (choose type from Beasts) |
| 4 | 1 adult black dragon or roll on Monsters lvl 11+ |
| 5 | 4d6 merrow or 1 marid with 1d6 dolphin delighters (MotM) |
| 6 | 1 aboleth with 2d4 chuuls or roll on Monsters lvl 11+ |
| 7 | 3d6 killer whales or 1 merfolk wavebender with 2d4 giant squid |
| 8 | 1d3 marids or roll on Monsters lvl 11+ |
| 9 | 2d4 giant sharks or 1 wastrilith (MotM) |
| 10 | 1 dragon turtle or roll on Monsters lvl 11+ |
| 11 | Roll on Underwater Encs lvl 5-10; or 1 morkoth (MotM) |
| 12 | 1 sahuagin baron with 4d6 sahuagin warriors and 1d6 sahuagin priests |
| 13 | 1 storm giant with 1d3 killer whales or 1d2 aboleth |
| 14 | 2d4+2 sahuagin priests each with a hunter shark |
| 15 | 2d4 water elementals or 1 archduid (MotM) |
| 16 | 1d3 storm giants or 1 archduid (MotM) with... (roll on Beasts) |
| 17 | 1 marid & 1d4 water elementals or 1 storm giant quintessent (MotM) |
| 18 | 1 sahuagin baron and 1d4+2 giant sharks or 2 young black dragons |
| 19 | 1 kraken or 1 archmage and 1d6 gladiators with water breathing |
| 20 | 1 elemental cataclysm or 1 colossus |
Underwater Beasts (Levels 1-4)
| 1d8+1d12 | Underwater Beasts Levels 1-4 |
|---|---|
| 2 | 1 giant shark |
| 3 | 1 giant constrictor snake and 1d4+1 constrictor snakes |
| 4 | 1d3 plesiosauruses or 1d4 dolphins with 1 dolphin delighter (MotM) |
| 5 | 1 giant lobster (chuul with Int 2) |
| 6 | 1d3 hunter sharks or 1d2 dolphin delighters (MotM) |
| 7 | 4d6 playful seahorses |
| 8 | 1d4+1 reef sharks |
| 9 | 1d4 giant octopi |
| 10 | 2d6 giant seahorses |
| 11 | 1d3 swarm of piranhas or 3d6 dolphins (MotM) |
| 12 | 2d4 constrictor snakes |
| 13 | 1d2 killer whales |
| 14 | 3d6 inquisitive octopi or 1d4 saltwater crocodiles |
| 15 | 1d2 giant constrictor snakes |
| 16 | 2d6 giant crabs or 3d6 piranhas |
| 17 | 1 patch of awakened seaweed (awakened bush) |
| 18 | 1 archelon or 1 hunter shark and 1d4 reef sharks |
| 19 | 1 swarm of crabs (swarm of insects with swim 30 ft) |
| 20 | 1 aquatic shambling mound |
Underwater Humanoids (Levels 1-4)
| 1d8+1d12 | Underwater Humanoids Levels 1-4 | |
|---|---|---|
| 2 | 1 malenti (sahuagin warriors, sea elf form) or 1 kraken priest (MotM) | |
| 3 | Adventurers with water breathing - 1 tough, 1 scout, 1 noble, 1 priest and 1 guard | |
| 4 | 1d4 sahuagin warriors and 1 sahuagin priest or roll on Sahuagin lvl 1-4 | |
| 5 | 1d6 merfolk skirmishers with 1d6 giant seahorses | |
| 6 | 1 sea elf berserker (swim 30 ft.) with 1 giant seahorse | |
| 7 | 1d3 merfolk skirmishers with 1d3 sea elf guards (swim 30 ft.) & 1 druid | |
| 8 | 1d6 lizardfolk pirates diving from the surface | |
| 9 | 1d2 merrow or 1d4 lacedons | |
| 10 | 1d6 sea elf scouts (swim 30 ft.) | |
| 11 | 2d6 merfolk skirmishers or 1 deep scion (MotM) | |
| 12 | 2d4 sahuagin warriors or roll on Sahuagin lvl 1-4 | |
| 13 | 1 sea hag with... (roll on Beasts) | |
| 14 | 2d4 fish folk (kuo-toa) or 1d4 sea spawn (MotM) | |
| 15 | 1d4+1 sahuagin warriors and 1d4 reef sharks or roll on Sahuagin lvl 1-4 | |
| 16 | 1 lizardfolk geomancer (can change into a giant octopus) | |
| 17 | 1 druid or 1d4 merfolk skirmishers with 1 dolphin delighter (MotM) | |
| 18 | 1 kuo-toa whip with 1d4 kuo-toa from the Underdark | |
| 19 | 1d4 sahuagin warriors with 1 sahuagin priest or roll on Sahuagin lvl 1-4 | |
| 20 | 1 mage with a cap of water breathing |
Underwater Monsters (Levels 1-4)
If required give creatures the amphibious trait:
Amphibious. This creature can breathe air and water
| 1d4+1d6 | Underwater Monsters Levels 1-4 |
|---|---|
| 2 | 1 sea troll (swim 30 ft.) or 1 roper (swim 10 ft.) |
| 3 | 1d2 grells (swim 30 ft.) or 1 flail snail (MotM) |
| 4 | 1 sea pudding (black pudding with swim 20 ft.) |
| 5 | 1 chuul or 1 slithering tracker (MotM) |
| 6 | 1d2 merrow or 1d2 deep scions (MotM) |
| 7 | 1d4+1 seaweed blights (vine blight, swim 30 ft) or 1 helmed horror (swim 30 ft.) |
| 8 | 1 sea hag or roll on Spirits lvl 1-4 |
| 9 | 1d2 gibbering mouthers or 1d4 lacedons |
| 10 | 1 water elemental or roll on Spirits lvl 1-4 |
Underwater Monsters (Levels 5-10)
| 1d4+1d6 | Underwater Monsters Levels 5-10 |
|---|---|
| 2 | 1 young dragon (black, bronze, gold or green) or 1 morkoth (MotM) |
| 3 | 1d2 hydras or 1d2 sea cloakers (swim 40 ft.) |
| 4 | 1 sea troll (swim 30 ft.) with 1d6 merrow |
| 5 | 1d6 chuuls 1 spirit naga (swim 40 ft.) |
| 6 | 1d3 giant squids or 1 froghemoth (MotM) |
| 7 | 1 aboleth or 1 hydroloth (MotM) |
| 8 | 1 water elemental and 2d6 mud mephits or roll on Spirits lvl 5-10 |
| 9 | 1 seaweed monster (treant, swim 30 ft.) or 1d2 cyclops (swim 30 ft.) |
| 10 | 1 marid or roll on Spirits lvl 5-10 |
Underwater Monsters (Levels 11+))
| 1d4+1d6 | Underwater Monsters Levels 11+ |
|---|---|
| 2 | 1 empyrean or 1 nightwalker (MotM) |
| 3 | 1 kraken or 1 retriever (swim 40 ft.) (MotM) |
| 4 | 1 purple worm (swim 50 ft.) or 1 wastrilith (MotM) |
| 5 | 1d2 storm giants or 1d4 hydroloths (MotM) |
| 6 | 1 dragon turtle or 1 morkoth (MotM) |
| 7 | 1d3 marids or 1 iron golem (swim 30 ft.) |
| 8 | 1 adult dragon (black, bronze, gold or green) or 1 leviathan (MotM) |
| 9 | 1 aboleth with 1d6 chuul or 1 death tyrant (swim 30 ft.) |
| 10 | 1 elemental cataclysm or 1 collisus |
Underwater Spirits (Levels 1-4)
| 1d4+1d6 | Underwater Spirits Levels 1-4 |
|---|---|
| 2 | 1 water elemental or 1 couatl (swim 90 ft.) |
| 3 | 1d3 drowned spirits (specter with swim 50 ft.) |
| 4 | 1 water weird or 1 murk demon (shadow demon, swim 30 ft.) |
| 5 | 1d4+1 steam mephits or 1 bone naga (swim 30 ft.) |
| 6 | 2d4 mud mephits or 2d6 merfolk skirmishers |
| 7 | 1d4 lacedons or 1 sea hag |
| 8 | 1d4+1 ice mephits or 1d2 sword wraith warriors (MotM, swim 20 ft.) |
| 9 | 1 sea elf spirit (banshee, swim 30 ft.) |
| 10 | 1 sea hag with... (roll on Beasts) |
Underwater Spirits (Levels 5-10)
| 1d4+1d6 | Underwater Spirits Levels 5-10 |
|---|---|
| 2 | 1d2 devils of the deep (chain devil, swim 30 ft.) |
| 3 | Coven of 3 sea hags or 1 water elemental and 2d6 mud mephits |
| 4 | 1d2 drowned shades (wraith with swim 60 ft) and 2d4 drowned spirits (specter, swim 50 ft) |
| 5 | 1d3 sea stalkers (invisible stalker, swim 50 ft.) |
| 6 | 1d4 water elementals or 1 brine naga (spirit naga, swim 40 ft.) |
| 7 | 1d2 seaweed blights (vine blight, swim 30 ft) led by 1 shambling seaweed (shambling mound) |
| 8 | 1 merfolk wavebender and 1d4 archelons |
| 9 | 2d4 drowned knights (wight, swim 30 ft.) |
| 10 | 1 marid |
More Encounters
There is a 5e Underwater random encounter generator at ChaosGen. There is also a pdf of these and more tables at the DM's Guild as Underwater Encounters.
If you liked these there are D&D Generators at Chaos Gen, a monthly random tools Newsletter and an instagram of Random Tables.
