d100 Underwater Finds

A d100 list of found objects, unexpected sights, and strange encounters for your players to come across while swimming through lakes, oceans, and marine trenches.

What lies below the water’s surface?

Over the course of their journey, adventurers may be required to leave the security of solid ground and brave unfathomable waters. Whether they’re floating above the waves or delving below them, the underwater seascape is a unique terrain worth incorporating into any adventure.

Versatility is the main appeal of underwater terrain. The most obvious instance would be the open ocean, but parties might happen upon bodies of water in any terrain. They could find an unnaturally still lake in the midst of a forest or a subterranean sea with unknowable depths. While this list details strictly underwater finds, it could be used to enhance your adventures through any of the other terrains as well.

When using this list, feel free to choose any options you particularly like. You can also let fate decide and roll a d100. Every fifth option in the list is more consequential than the rest, so roll a d20 and multiply by 5 if you want to ensure a truly unique encounter for your party.

D100 Underwater Finds

1. A cluster of unknown fish eggs. The parents can’t be far.
2. The remains of some carnivorous school’s feeding frenzy.
3. A skeleton in armor that was too heavy to swim.
4. A solitary eye floating on the surface.
5. [Encounter] A water elemental hides under the water, attempting to drown any who submerge.
6. A school of fish that parts for any creature entering their space.
7. A trio of glowing eyes are revealed to be three gemstones set in a tiara on closer inspection.
8. The ringing of a bell can be heard while a creature’s ears are submerged in the water, but it is impossible to locate the source.
9. Seaweed and other underwater debris seem to cling and grasp at characters, as if trying to prevent them from reaching the surface.
10. A sea turtle as large as an adult dragon swims lazily about. Its back is covered in a mix of land and sea flora and fauna. Being on the turtle’s back allows one to breath both air and water, and also grants the benefits of a long rest after only an hour. The turtle doesn’t seem to mind hop ons.
11. A glowing fish that is not normally bioluminescent.
12. A glass orb filled with a strange, inky liquid.
13. Two dolphins that follow the party for a while then vanish.
14. Humanoid footprints, as if someone were walking along the bottom.
15. [Encounter] A raiding party of sahuagin riding sharks crosses paths with the adventurers (DM can change the number of enemies to fit party level and number).
16. A child sized shoe floating in the water.
17. Dead fish litter the surface. The water isn’t poisonous to characters that breathe only air, but will poison amphibious adventurers.
18. The skull of a giant piscine creature rests on the bottom.
19. An abandoned dinghy floats nearby. It is stocked with supplies for a long sea voyage, but there is no sign of anyone onboard.
20. The party comes across the floating city of Seaholme. It is a shifting city made out of ships, rafts, flotsam, and various other floating objects bound together. Ships can attach to the city and detach as needed. The water around Seaholme is always calm. There are various merchants, grocers, traders, and fisheries throughout the city for characters to explore (for additional fun, sea monsters might attack the city while the party is visiting).
21. A number of glass bottles float in the water.
22. A stone statue of an armor-clad humanoid magically floats just below the surface. The features are too worn to know who it represents.
23. A fish with two heads swims in a perfect circle. It’s unclear how it has survived to adulthood.
24. A warm updraft from a narrow crevice under the water. It is too small for anyone to enter, but the timing between drafts resembles breathing.
25. A lone humanoid sits on the surface of the water. He calls himself Ibn Yasir. He says that he can teach the party to walk on the water as well. He is lying and wants to pull a prank on the party. He offers them a ring of water walking if they take his joke in good humor.
26. A reef with multi-colored rocks and foliage.
27. An old chest. Inside are a few silver pieces, rotting clothes, and a gold medallion.
28. An underwater cave. A group of albino lobsters live inside. On the back wall, “Consider the lobsters well” is scrawled in magic ink.
29. Dark shapes can be seen swimming nearby, but it is impossible to make out what they are. They pass under or over the party briefly, causing them to shiver involuntarily.
30. A wooden totem carved in the shape of a crab pokes out of the water here. It stretches as far as it needs to reach the bottom of the body of water it is in. Touching the totem causes the water around it to part in a 25-foot radius. Any creatures occupying the area around the totem begin falling after it it touched. The water closes back in around the totem after one minute.
31. A bird sits on the water’s surface. It notices the party and says “There is no bottom here” before flying away.
32. An eel with a humanoid rib bone in its jaws.
33. A tiny wooden ship that might have been a child’s toy.
34. The mirage of an island in the distance.
35. [Encounter] The wreck of a galleon reforms itself into a sentient construct that attempts to destroy any other ships in the vicinity (have as much fun as possible creating this monster’s stat block! Don’t go easy on them).
36. Blood in the water.
37. Strange dragonflies flit over the water. They gleam even in moonlight.
38. A spectral face appears in the water for a brief moment. It is twisted in agony.
39. Children’s laughter is carried on the breeze, but it is impossible to find the source.
40. A mask bobs to the surface. It bears the face of a party member. If any other character puts the mask on they look exactly like their compatriot. If the party member the mask resembles puts it on, it melds into their face and they forget who they are for 24 hours. Even after the effect wears off, they never truly feel like themself again.
41. An inky-black film covers the water. It clings to anyone in contact with it and makes it nearly impossible to swim.
42. A floating barrel. There are carrots, potatoes, and cauliflower in various sacks inside. They have remained surprisingly dry.
43. A deep voice can be heard underwater from all around. Its words are in an ancient, unknown language.
44. A bundle of cloth floats nearby and the crying of an infant can be heard coming from it. Opening the bundle reveals nothing inside and stops the crying sound.
45. An aquamarine scarf can be seen floating nearby. It is cursed and once worn cannot be removed unless the curse is removed. Wearing the scarf convinces a character that they can breathe underwater, even as they drown.
46. A bowl containing green liquid floats on the surface. The liquid smells of apples, but tastes like pomegranate.
47. Evidence of an underwater battlefield with merfolk and sahuagin corpses.
48. An old underwater temple to a party member’s favored deity. It was clearly above water at one point, but now is a home for many fish, crustaceans, and amphibians.
49. A rusted helmet and sword.
50. A merfolk town. They are wary of surface-dwellers, but willing to trade. They have a number of aquatic themed weapons and armor, raw fish, minor potions, and magic items for sale. They can also provide knowledge of the party’s destination and the underwater surroundings.
51. A whale breaches nearby.
52. Scraps of clothing splattered with blood.
53. A magically water-proofed pair of pants that always stay dry.
54. The wreck of a number of ships. The party hears cries of help from far away, but drawing nearer they can’t seem to find any survivors.
55. [Encounter] The party stumbles into a marid’s lair. The marid threatens to keep them as slaves for their unannounced entrance unless they can provide a satisfactorily entertaining tale from their adventures. Reward extra XP for any particularly well told stories.
56. A number of seabirds circle above the water, forming strange symbols with their flight patterns.
57. A bottle containing a treasure map.
58. A candle burns underwater. Removing it from the water snuffs it out.
59. A crustacean and mollusk enclave has formed on a large piece of driftwood. There are a large amount of crabs, lobsters, clams, shrimp, and oysters.
60. [Encounter] An aboleth has enslaved an underwater city of tritons and wants to add the party to its growing workforce.
61. A thing. It is impossible to describe. It is a fish, maybe? But what are those wings for? And is that an elephant’s trunk?
62. The water reeks horrifically, potentially causing characters to vomit. It has a greenish tinge and seems devoid of animal or plant life.
63. A blank journal in a waterproof pouch.
64. A jellyfish with a rat caught in its tentacles.
65. The party finds a cave underwater that has a magical airpocket. The air inside smells like lightning. Any characters that take a long rest inside the cave gain resistance to lightning damage for one week.
66. A mechanical fish about the size of a hand.
67. An amethyst geode.
68. Two swordfish battling.
69. A crab with coral growing on it.
70. A pillar of stone lies underwater with eight holes in concentric rings of four each at different heights. If any player gets within ten feet of a hole, a large eel emerges to attack them.
71. A sunken shipwreck. It was carrying produce and foodstuffs that have all become waterlogged and inedible.
72. A bottle that has become the home of an octopus. It will defend itself if provoked.
73. A gilded letter-opener covered in barnacles. It can be salvaged and sold.
74. A swarm of jellyfish that glow an eerie green color.
75. [Encounter] A wereshark! (Stating this monster should be fun!)
76. A field lilies and other water flowers float in a cluster on the surface.
77. A glass disk about the size of a pumpkin.
78. A sea turtle with a compass drawn on its shell.
79. The party spots an old cabin at the bottom. The only things inside are a school of fish and a broken table.
80. A hidden underwater cave leads to a large subterranean lake. An island in the middle is covered with white flowers. At the center of the island is a magic weapon (DM’s discretion). The flowers are blood drinking plants that have razor sharp petals and are coated in a numbing secretion so that creatures will hardly notice the deep cuts.
81. A singing clam. Its song is garbled by the water.
82. A painting of a male elf that remains pristine despite being submerged. Its eyes seem to follow the characters.
83. Whale songs can be heard underwater.
84. A field of seaweed. Something appears to be moving within it, but the party can never get close enough to discern it.
85. A lone fisherman in a rowboat. He says that he is hunting after a mythical beast that no one has ever seen before; not even him! He cannot be persuaded that it doesn’t exist. Who’s to say if its real or not though? The DM!
86. An old, rusted spyglass with the letters “R.M” etched into the side.
87. Three empty cauldrons arranged in a pyramid.
88. An idol of a sea-serpent with average-sized sapphires set in its eyes.
89. A one-finned fish that follows the party.
90. A violent storm! Chaos and calamity breaks out as rain, hail, lightning, and whirpools suddenly close in around the party. It passes after a few minutes and a faint booming “My apologies!” can be heard as the storm that passed over them continues on its way.
91. A cube made entirely of ice. Melting or breaking it will reveal a dead, preserved humanoid corpse with an ice-themed spell tome on their person.
92. A trench hundreds of feet deep. Strange, foreign fish that few have seen live in its depths.
93. The water smells like peaches here. It tastes like them too.
94. A corpse rests on a lone rock pillar jutting above the water. In a satchel next to it is an unsent love letter and a crab.
95. [Encounter] A stone slab rises from the water with an animated armor and a corpse on it. looks to be protecting the corpse, which has a magic staff in its grasp (DM’s choice). The armor wields a flying sword and will attack any creature that approaches its creator’s corpse.
96. A family of otters holding hands to avoid being separated.
97. A tattered sail bearing a famous noble house’s coat-of-arms.
98. A small island with a single tree and a breed of sheep thought to be extinct.
99. A flute carved out of a shell.
100. [Encounter] A representative of a sea god approaches the party with an offer from the deity; clear an underwater temple of a kraken and be reward with otherworldly power. A high enough check of an appropriate nature reveals that this is not a representative of a sea god, but one of the kraken’s cultists. They are trying to lure more prey/slaves to its lair.