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5E DnD Underwater Encounters
D&D Encounters Underwater

5E DnD Underwater Encounters

Duncan Thomson

"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."

Why are these creatures fatigued?

Underwater Encounter Tables - creatures | locations | non-combat | enhancements

[Photo by Scott Webb on Unsplash]. Updated from original article in 2018

Underwater Levels 1-4

1d8+1d12Underwater Levels 1-4
2 1 giant shark or 1 kraken priest (VGtM)
3 1d3 plesiosauruses or 1 sea hag with 1d2 sea spawn (VGtM)
4 1d4 sahuagin with 1 sahuagin priestess or roll on Sahuagin lvl 1-4
5 2d6 giant crabs or roll on Underwater Beasts
6 1d2 chuul or roll on Underwater Monsters lvl 1-4
7 1d4+1 reef sharks or roll on Underwater Beasts
8 1d3 sahuagin and 1d3 reef sharks or roll on Sahuagin lvl 1-4
9 1d3 giant octopi or roll on Underwater Beasts
10 1d2 merrow or roll on Underwater Monsters lvl 1-4
11 2d6 giant seahorses or roll on Underwater Beasts
12 2d6 merfolk or roll on Underwater Humanoids
13 1d3 killer whales or 3d6 dolphins (VGtM)
14 2d4 steam mephits or roll on Underwater Spirits lvl 1-4
15 1d3 hunter sharks or 1d4 sea spawn (VGtM)
16 2d4 merfolk with 2d4 giant sea horses or roll on Underwater Humanoids
17 1d3 swarms of quippers or 1 deep scion (VGtM)
18 1 sea hag and 1d2 swarms of quippers or roll on Underwater Spirits lvl 1-4
19 1 giant constrictor snake or 1 druid
20 1 water elemental or 1 sea elf spirit (banshee stats)

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

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.

Ruins Encounters Random Tables on DM's Guild Ruins Encounters Random Tables on DM's Guild

All terrains - arctic | coastal | desert | forest | grassland | hill | jungle | mountain | swamp | underdark | underwater | urban

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 5-10

1d8+1d12Underwater Levels 5-10
2 1 marid or 1 morkoth (VGtM)
3 1d3+1 giant sharks
4 2d6+2 sahuagin led by a sahuagin baron or roll on Sahuagin lvl 5-10
5 1d4+1 giant constrictor snakes or 1 hydroloth (MToF)
6 A coven of 3 sea hags or roll on Underwater Spirits lvl 5-10
7 3d6 sahuagin and 1d3 sahuagin priestesses or 1 mage with water breathing served by 1 water elemental myrmidon (MToF)
8 1d4 water elementals or roll on Underwater Spirits lvl 5-10
9 4d6 merfolk with 3d6 giant seahorses
10 2d6 sahuagin and 1d4+1 hunter sharks or roll on Sahuagin lvl 5-10
11 Roll on Underwater Levels 1-4 table or 3d6 sea spawn (VGtM)
12 1d4+2 killer whales
13 1d2 hydras or roll on Underwater Monsters lvl 5-10
14 1d4+1 chuuls or 2d6 hunter sharks
15 1 sea troll (swim 30 ft.) with 1d6 merrow or roll on Underwater Monsters lvl 5-10
16 2d6 plesiosauruses or 1 kraken priest (VGtM) with 1d4 cult fanatics (with water breathing)
17 1 aboleth or roll on Underwater Monsters lvl 5-10
18 1 sea hag and 2d4 merrow
19 1 young black dragon or 1 kraken priest (VGtM) with 1d4+1 deep scions (VGtM)
20 1 storm giant

Underwater Levels 11+

1d8+1d12Underwater Levels 11+
2 1 adult black dragon or 1 leviathan (MToF)
3 1 kraken
4 2 young black dragons or roll on Underwater Monsters lvl 11+
5 4d6 merrow or 1 storm giant quintessent (VGtM)
6 1 aboleth with 2d4 chuuls or roll on Underwater Monsters lvl 11+
7 3d6 killer whales or 1 wastrilith (MToF)
8 1d3 marids or roll on Underwater Monsters lvl 11+
9 2d4 giant sharks or 1d2 aboleth
10 1 dragon turtle or roll on Underwater Monsters lvl 11+
11 Roll on Underwater Levels 5-10 table or 1 morkoth (VGtM)
12 4d6 sahuagin and 1d4+2 sahuagin priestesses led by a sahuagin baron
13 1 storm giant with 1d3 killer whales
14 2d4+2 sahuagin priestesses each with a Hunter Shark
15 2d4 water elementals or 1 archduid (VGtM)
16 1d3 storm giants
17 1 marid and 1d4 water elementals or 1 archduid (VGtM) with... (roll on Beast Encounters)
18 1 sahuagin baron and 1d4+2 giant sharks
19 1 archmage and 1d6 gladiators with water breathing
20 1 empyrean or 1 lich

Underwater Beasts (Levels 1-4)

1d8+1d12Underwater Beasts Levels 1-4
2 1 giant shark
3 1 giant constrictor snake and 1d4+1 constrictor snakes
4 1d3 plesiosauruses
5 1 giant lobster (chuul stats with Int 2)
6 1d3 hunter sharks
7 4d6 playful sea horses
8 1d4+1 reef sharks
9 1d4 giant octopi
10 2d6 giant seahorses
11 1d3 swarm of quippers or 3d6 dolphins (VGtM)
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 quippers
17 1 patch of awakened seaweed (use stats of awakened bush)
18 1 hunter shark and 1d4 reef sharks
19 1 swarm of crabs (swarm of insects stats of with swim 30 ft)
20 1 aquatic shambling mound

Underwater Beasts (Levels 1-4)

1d8+1d12Underwater Beasts Levels 1-4
2 1 giant shark
3 1 giant constrictor snake and 1d4+1 constrictor snakes
4 1d3 plesiosauruses
5 1 giant lobster (chuul stats with Int 2)
6 1d3 hunter sharks
7 4d6 playful sea horses
8 1d4+1 reef sharks
9 1d4 giant octopi
10 2d6 giant seahorses
11 1d3 swarm of quippers or 3d6 dolphins (VGtM)
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 quippers
17 1 patch of awakened seaweed (use stats of awakened bush)
18 1 hunter shark and 1d4 reef sharks
19 1 swarm of crabs (swarm of insects stats of with swim 30 ft)
20 1 aquatic shambling mound

Underwater Humanoids (Levels 1-4)

1d8+1d12Underwater Humanoids Levels 1-4
2 1 malenti (sahuagin stats, sea elf form) or 1 kraken priest (VGtM)
3 Adventurers with water breathing - 1 thug, 1 scout, 1 noble, 1 priest and 1 guard
4 1 priest missionary (replace dispel magic with water breathing)
5 1d6 merfolk with 1d6 giant sea horses
6 1 sea elf berserker (swim 30 ft., Stealth +3, Survival +2) with 1 giant seahorse
7 1d3 merfolk with 1d3 sea elf tribal warriors (swim 30 ft.) and 1 druid
8 1d6 lizardfolk diving from the surface
9 1d2 merrow
10 1d6 sea elf scouts (swim 30 ft.)
11 2d6 merfolk or 1 deep scion (VGtM)
12 2d4 sahuagin or roll on Sahuagin lvl 1-4
13 1 sea hag with... (roll on Beast Encounters)
14 2d4 fish folk (kuo-toa stats) or 1d4 sea spawn (VGtM)
15 1d4+1 sahuagin and 1d4 reef sharks or roll on Sahuagin lvl 1-4
16 1 lizardfolk shaman (can change into a giant octopus)
17 1 druid
18 1 kuo-toa whip with 1d4 kuo-toa from the Underdark
19 1d4 sahuagin with 1 sahuagin priestess 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+1d6Underwater 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 (VGtM)
4 1 sea pudding (black pudding stats with swim 20 ft.)
5 1 chuul or 1 slithering tracker (VGtM)
6 1d2 merrow or 1d2 deep scions (VGtM)
7 1d4+1 seaweed blights (vine blight stats, swim 30 ft) or 1 helmed horror (swim 30 ft.)
8 1 sea hag or roll on Underwater Spirits lvl 1-4
9 1d2 gibbering mouthers
10 1 water elemental or roll on Underwater Spirits lvl 1-4

Underwater Monsters (Levels 5-10)

1d4+1d6Underwater Monsters Levels 5-10
2 1 young dragon (black, bronze, gold or green) or 1 morkoth (VGtM)
3 1 spirit naga (swim 40 ft.) or 1d2 cyclops (swim 30 ft.)
4 1 sea troll (swim 30 ft.) with 1d6 merrow
5 1d6 chuuls or 1d2 sea cloakers (swim 40 ft.)
6 1d2 hydras or 1 froghemoth (VGtM)
7 1 aboleth or 1 hydroloth (MToF)
8 1 water elemental and 2d6 mud mephits or roll on Underwater Spirits lvl 5-10
9 1 seaweed monster (treant stats, swim 30 ft.)
10 1 marid or roll on Underwater Spirits lvl 5-10

Underwater Monsters (Levels 11+)

1d4+1d6Underwater Monsters Levels 11+
2 1 empyrean or 1 elder brain (VGtM)
3 1 kraken or 1 retriever (swim 40 ft.) (MToF)
4 1 purple worm (swim 50 ft.) or 1 wastrilith (MToF)
5 1d2 storm giants or 1d4 hydroloths (MToF)
6 1 dragon turtle or 1 morkoth (VGtM)
7 1d3 marids or 1 marilith (swim 40 ft.)
8 1 adult dragon (black, bronze, gold or green) or 1 leviathan (MToF)
9 1 aboleth with 1d6 chuul or 1 death tyrant (swim 30 ft.)
10 1 iron golem (swim 30 ft.) or 1 nightwalker (MToF)

Underwater Spirits (Levels 1-4)

1d4+1d6Underwater Spirits Levels 1-4
2 1 water elemental or 1 couatl (swim 90 ft.)
3 1d3 drowned spirits (specter stats with swim 50 ft.)
4 1 water weird or 1 murk demon (shadow demon stats, swim 30 ft.)
5 1d4+1 steam mephits or 1 bone naga (swim 30 ft.)
6 2d4 mud mephits
7 1 sea hag
8 1d4+1 ice mephits or 1d2 sword wraith warriors (MToF, swim 20 ft.)
9 1 sea elf spirit (banshee stats, swim 30 ft.)
10 1 sea hag with... (roll on Beast Encounters)

Underwater Spirits (Levels 5-10)

1d4+1d6Underwater Spirits Levels 5-10
2 1d2 devils of the deep (chain devil stats, swim 30 ft.)
3 Coven of 3 sea hags
4 1d2 drowned shades (wraith stats with swim 60 ft) and 2d4 drowned spirits (specter stats, swim 50 ft)
5 1d3 sea stalkers (invisible stalker stats, swim 50 ft.)
6 1d4 water elementals
7 1d2 seaweed blights (vine Blight stats, swim 30 ft) led by 1 shambling seaweed (shambling mound stats)
8 1 water elemental and 2d6 mud mephits
9 2d4 drowned knights (wight stats, 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.

Ruins Encounters Random Tables on DM's Guild Ruins Encounters Random Tables on DM's Guild

You can get random generators updates on Patreon or join the Rand Roll Discord Server