Thumbnail art by Christian Dimitrov

In case you didn’t know, the Under the Seas of Vodari Kickstarter is fully backed and new stretch goals keep getting obliterated. Thank you very much for this! The book is something great to work on and you are helping make it happen! If you didn’t back it yet, go do so now! It’s full of great underwater locations, cultures, subclasses, magic items, and MUCH MORE! (including my fearsome monsters). Never have I seen some other campaign settings try out something similar. This article will still be waiting for you when you come back.

All right then, in commemoration of the Kickstarter success, I’ve decided to make some Undersea encounters for you to have ready when your players decide to dive into the deep seas. If you are looking for encounters that aren’t underwater by over it, you can check out this article: 20 Sea Encounters. However, if it is Pirate ports or Coastal cities’s encounters what you are looking for, check right here: Encounters for Pirate and Coastal Cities

Let’s leave all that behind and dive into what you really came for in this article!

20 Undersea encounters

Roll a d20 (or 2d10 if you want the ones in the center to have a higher chance of happening):

1. The pulsing coin

A DC16 Wisdom (Perception) check shows a coin in the bottom of the sea shining. If the player characters decide to get closer to it the coin starts sending waves of energies rhythmically in a 2000ft. radius around it. The coin is made out of gold and displays a reptilian eye in it. After 5 turns, 2d6 merrow appear. They seem to be a hunting party from what they are wearing.

The coin is a Good Luck Trinket of Arr’hankaj. A DC18 Intelligence (History) check reveals Arr’hankaj to be a lizardfolk deity of luck followed primarily by lizardfolk pirates. The trinket absorbs all blood within 10 ft. of it. If it has received blood in the last turn, it grants a Luck point similar to the ones from the Lucky feat. The Good Luck Trinket of Arr’hankaj can only give up to two luck points to the creature that has it per long rest.

2. The leviathan

At first, it seems as if a giant island was moving underwater, except it is nowhere near to the surface. A DC16 Intelligence (Investigation) check reveals the island to be a gargantuan creature moving in the PC’s direction when it is at 150ft from the PCs. It is a  giant leviathan turtle coming towards them.

The giant leviathan turtle is a dragon turtle with the following changes:

  • It is black in color and has a black spine on its back
  • Replace the Steam Breath attack for the ancient blue dragon‘s Lightning Breath (looks blue in color and in the shape of  an energy beam)

The giant leviathan turtle isn’t looking for a fight. It wanted easy food. If the PCs fight it enough to scare it off, the turtle leaves. If the player characters seem to be using all their fire power against it, the giant leviathan turtle will fight until it has one of the PCs drop unconscious. When that happens, the giant leviathan turtle asks the PCs to drop as many magic items as they can in its mouth as a fee to leave them alone. If the giant turtle drops below 100hp, it attempts to escape at full speed, planning to take revenge on a later date. Otherwise, if the PCs attempt to run from the giant leviathan turtle, the creature takes curiosity in them and gives them chase at full speed.

3. The chanting storm giants

A group of 2d12 storm giants is chanting a melodious song that can be confused with a whale song if heard from afar. Their chanting is in Giant. As long as they continue singing, they are stopping great storms from happening in the surface. The storm giants are dedicated to protecting those who sail the seas in this area.

4. Underwater outpost

A small sea elves outpost appears in the distance. After a while, they send Zilv, a scout, to inspect the player characters and ask if they are lost. If the player characters treat Zilv well while explaining their reason to be there, Zilv invites them over to eat.

The outpost is home to a small community of sea elves. As the characters arrive, the “elder” Tirynn of the outpost comes to receive the characters. Roll a d4 on the following table to see how he reacts towards the PCs:

  1. Tirynn has heard stories about the PCs from a bard and wants to check if they are true, and hear more from them. Half the stories Tirynn heard are partly true but way off.
  2. Tirynn is furious about something he has heard the PCs have done in the past. He doesn’t want them anywhere near the outpost. The PCs can convince him to stay with a DC17 Charisma (Persuassion) check.
  3. Tirynn has heard great things about the PCs and after a good meal ask them to complete a mission for him. You can use one of the encounters as a mission or create your own.
  4. The elder reacts indifferently to the PCs. He doesn’t like adventurers as he thinks they only cause chaos wherever they go. He tries to not meet the PCs and talk to them even though many in the outpost will try to present the characters as the heroes of some previous mission they did to him.

Eating with those in the outpost grants the benefits of a long rest.

5. Underwater ruins

The PCs see an abandoned city at the bottom of the sea. Its buildings are mostly made out of rocks, but look collapsed. No creature roams the region around it. In what appears to be the ruins’ center, a tall pink coral obelisk stands. If player characters press a succession of runes inscribed in it in the correct order, some ladders around the pillar appear showing a way down towards a hidden dungeon.

6. Underwater goblin with a shark launcher (summons sharks)

A goblin is floating alone in the water, swimming in some direction. She is carrying a strange device that looks like a big gun and has gills on its neck. Something gave her the ability to breathe underwater and commanded her something. She is now charmed following orders. She is carrying a gun that when fired as an action summons sharks within 5ft of her that see her as an ally but act on their own will. The sharks act after the goblin in iniative order. The gun has 4 charges that are fired in the following order:

  1. Summons a giant shark
  2.  Summons a reef shark
  3. Summons a hunter shark
  4. Summons 4 giant sharks

Once the 4 charges are fired, the gun remains just a normal pistol from the DMG.

The goblin can’t remember her name, why she is following orders nor what she was supposed to do if the character remove the charm effect on her. If the characters try to talk with her while in this charmed state, she doesn’t talk back and deffends by using the weapon.

7. Giant whirlpool

You find yourselves in front of a 50ft radius whirlpool. Parts of destroyed ships, algae and some animals are caught spinning in it. The area around the whirlpool is divided in three spaces, each of them 20ft. wide. The player characters start in area 3. Have each player character roll a Strength (Athletics) check to get away from its center getting to the area adjacent to it. Failing the save moves the character closer to the center. For example, if you are in area 2 and fail the save, you are moved to area 1. If you succeed, you manage to swim to area 3. Below are the areas with their respective DCs:

  • Area 3: DC17
  • Area 2: DC20
  • Area 1: DC22

Failing the save on area 1 has the character fully trapped in the whirlpool moving full speed around it. Once it’s settled how many PCs are trapped witin it and how many are out of its grasp, start a skill challenge with those inside it using the many things trapped going in circles with the PCs. If you don’t know what a skill challenge is, you can find an explanation right here, explained by Matt Colville.

8. Sinking Pirate Ship

As the player characters continue their journey, those with a Passive Perception of 13 or higher hear a great commotion going on in the water surface. Two ships are in combat firing cannonballs at each other. That’s when one of the boats starts to sink. Some people float in the surface while others sink towards the bottom of the ocean unconscious.

If the player characters help those about to drown and lead them to safe ground they will be heavily recompensated and will have gained a new ally.

9. The metal juggernaut

A gargantuan metal vehicle is crashed against a rock surface. The PCs can enter through its hatch with a successful DC17 Strength (Athletics) check. The vehicle seems to have been used at some point by land-dwellers but it’s now filled with water. A successful DC16 Intelligence (Investigation) check has the characters understand this vehicle was prepared to be used at some war and has great missiles intended for great destruction. It takes a DC15 Intelligence (Tinker Tools) check to deactivate the missiles.

The vehicle seems to be some sort of submarine with its shape made to look like a sea animal. With 35.000 gp inverted in the vehicle, it could be possible to restore it back to a functioning state.

10. Jellyfish group

A gigantic group of jellyfishes moves in a certain direction all together. Making your way around the jellyfishes will probably add 3 more hours to the voyage. Going through its interior, on the other hand, seems extremely dangerous.

Attempting to go through the interior requires a skill challenge. You can make it as long as you want, but I do recommend having to get 6 successes before they get 3 failures. Every time the player characters fail at a check, they all take 4d10 lightning damage as several jellyfishes attack all at once.  Succeeding on the skill challenge means the characters crossed the jellyfish group successfully. Failing at it means the group falls unconscious for 1d6 hours in the interior of the jellyfish group as all the jellyfishes decide to attack the characters at once. If the characters require to breathe air to survive, have a fishing boat rescue the characters with a big net. Either way, they lose 1d4 hours until they all wake up in the boat.

 11. Inverted Storm

Thunderous noises start to be heard as a great mass of fishes swim in all directions away from it. The sounds come from the deep below. The sounds continue for some time and for every 10 minutes that pass there is a 10% chance one of the player characters gets hit by lightning coming from the bottom of the seas. Use the spell lightning bolt for the lightning damage. What could be causing this strange happening to occur?

12. Water currents

The player characters find themselves in front of a great water current. Roll a d4 to determine the way it is flowing (1: North; 2: East; 3: South; 4: West). The characters may decide to jump in it with the several animals that are also traveling there. The water current moves at 10 miles per hour. There is a 50% chance the player characters encounter a complication in it:

Roll a d4:

  1. A killer whale is traveling in it as well and gives the characters chase.
  2. A group of 4 sea gnomes are charging those who travel through the current 5gp each. They claim to be the ones that are creating the water current.
  3. 2d6 sahuagins are giving chase to 1d4 sea elves as they all travel in the water currents. The sea elves plead for help as they come close to the characters.
  4.  The water current is extremely strong and requires a DC16 Strength (Athletics) check to leave it. The sea current seems to redirect towards the bottom of the ocean.

13. Volcano

An underwater volcano in the zone activates causing the water near it to boil. If the characters decide to continue in this pass, they are going to have to make a DC17 Constitution saving throw for every minute they decide to stay there, otherwise taking 4d6 fire damage on failures.

14. A merfolk needs help

The player characters encounter a merfolk pleading for help as they have lost its stingray pet when a shark approached the area. The merfolk is named Amina and says they will award the characters with a treasure map they found the week before if the characters find the stingray.

The stingray takes 4 hours to find, but the time can be reduced by one hour for every successful DC15 Wisdom (Perception) or DC14 Wisdom (Survival) check made. Using locate creature or similar magic reduces the time to find the stingray by two hours.

When the characters finally find it, the stingray is cornered by 1d6 sahuagins, and 1d4 hunter sharks that obey the sahuagins orders.

15. Sunken Trapped Chest

A chest lies covered by kelp at the bottom of the seas that can be seen with a successful DC15 Wisdom (Perception) check. The chest has a symbol of a shrimp flexing on its lid. The chest is trapped with an arcane lock spell (DC21) and weighs 180 pounds.

The chest has in its interior 6d12 pp, 6d10 x 10 gp, and 3d20 x 50 cp. Additionally, it contains 1500gp worth in gemstones, a treasure map, a message cursing those who open the chest and a compass that always points east.

16. Racing Sahuagins

6 sea horses carrying one sahuagin each pass next to the characters at full speed. Following them the player characters encounter a tournament taking place. It is a sea horse race. Players must first convince the sahuagins to be let in, which can be done with a successful DC 14 Charisma (Persuasion) or Charisma (Intimidation) group check. In it, players can decide to bet in the races, or take part in them. Doing the latter can guarantee winning 1d4 giant sea horses as prizes if the character gets the first place. Taking part in the race costs 15 gp each.

17. Sea elves class

The player characters encounter a group of 30 young sea elves being led by two older sea elves (use commoner stat block for them). They went in a school excursion to see different underwater creatures. One of the teachers is playing music with a weird flute as the other one says that playing that music in this location attracts what are known as “sea monkeys”. If the characters decide to stay and see, they will see that within the next minute 1d12 sea monkeys appear. They dance to the music for a while and proceed to leave after 10 minutes. While this is going on, the other teacher is explaining the whole anatomy of the creature. If the music is disrupted, the sea monkeys attack those they have nearby until killed.

Sea monkeys are giant apes that can breathe underwater.

18. Festival

The characters accidentally find themselves into a festival. This festival is celebrated by the sea elves where there is music, food, clothing, and dances held and given to those who attend. It is a festival that uses lots of fluorescent lights that shine with numerous colors during the night. Land-dwellers usually come to this location on ships to see the lights under the sea, considering it a strange phenomenon.

19. The Kraken

Have the characters make a DC16 saving throw as a Kraken that was camouflaging against some rocks shows itself by throwing a tentacle attack towards the characters. On a failure, the Kraken deals 3d6+10 bludgeoning damage to the target. 4 Kraken emissaries (use the priest stat block for them) show from below the Kraken, stating that the characters are now entering its domain. The characters must leave or be attacked by the creature and those who follow it. The Kraken is known as “The one who hungers” in Deep Speech.

20. The blue whale

As the characters keep swimming, they hear a strange disturbing noise that travels all across the region. That’s the song of a whale, as those that succeed on a DC16 Intelligence (Nature) check will recognize. 10 minutes later, a gargantuan blue whale swims next to the characters. Characters may decide to grab it to travel with the blue whale. The animal is so big it doesn’t care if creatures attach to it. This is a weird phenomenon that is rarely seen as there aren’t many blue whales in the ocean.

If you liked this

Did you know I create Monthly Encounters for Tribality? I’m about to reach 20 different encounters for all level Tiers that you can grab and easily insert in your game. You can find them all indexed here: CLICK HERE