60+ D&D 5e Sea Encounters

Are your players heading out to sea? Have an ocean-bound adventure planned to take your D&D game to the waves? Or, has your party somehow found themselves in the middle of the Elemental Plane of Water?

The ocean is a vast obstacle in its own right for players to overcome in Dungeons & Dragons and other TTRPGs. So, filling it with things to do can be daunting despite the limitless creativity available to Game Masters.

That’s why I’ve put together a list of over 60 random sea encounters for 5e.

These encounters span the Tiers of Play so GMs have options for any player character level. If you use any of these sea encounters, please let me know in the comments below or tag me on Twitter, @RolePlayRespite.

Without further ado, here are 64 sea encounters for 5e organized in four 3d6 tables by the Tiers of Play!

D&D Sea Encounters: Tier 1 (1st-4th Levels)

3. Water Elemental Attack: A Water Elemental and 1-2 Steam Mephits emerges from the waves and attacks.
4. Siren’s Song: As the party’s vessel passes by a small, sandy island, they spot 1-4 humanoid-looking figures resting along the beach. A DC 16 Wisdom (Perception) check reveals these to be merfolk in appearance but they have more elven-looking heads. If a player passes this check by 5 or more, they also notice something is wrong with these creature’s mouths, almost as if their cheeks have slit extending to their pointed ears. These creatures are Sirens (use the Harpy stat block but replace their fly speed with a swim speed). If the party gets within 300 feet, the Sirens use their Luring Song action.

5. Giant Shark Attack: The most perceptive party member spots an huge, submerged creature with a large fin passing by roughly 100 feet off the starboard side of their vessel and approaching fast. This is a hungry and aggressive Giant Shark which intends to attack the vessel.
6. Sudden Storm: A sudden storm whips up, making navigation harder for 1d10 hours. Any checks made to stay on course are made at disadvantage for the duration and progress and travel time slows.
7. Desperate Pirates: A band of 4-8 Pirates (use the Bandit stat block) is a small ship approach the party’s vessel, demanding they turn over any valuables or be boarded. These Pirates attempt to flee if 1/4 of their number get cut down.
8. Spoiled Food: One of the provisions on the party’s vessel contained almost rotting food which has spread to the rest of the supplies contained within. This effectively reduces the number of rations for the party by 2 days. A creature that attempts to eat the food must succeed on a DC 16 Constitution saving throw or become poisoned for 3d8 hours as they succumb to food poisoning.
9. A Brief Calm: The winds die down, halting travel time for 1d4 hours.
10. Merfolk Scouts: The party’s vessel passes by a group of Merfolk scouts. These merfolk are curious about the party’s intentions in these waters, wanting to ensure they mean no ill-will, and are otherwise unhelpful. They may have information regarding the state of the surrounding area if persuaded.
11. Moral Choice: The party comes across a nearly wrecked Sailing Ship belonging to an enemy nation / faction with only half its possible crew. These people don’t seem to want a fight, just to get home safely.
12. Clear Skies: Sailing is unimpeded, resulting in the party’s vessel making better time. Navigation checks are made at advantage for the rest of the day and travel time decreases by 1d8 hours.
13. Abundance: The most perceptive player character notices an unusually high number of fish in the surrounding waters. Checks made to procure food are made at advantage and character receive double the amount they normally would for the next 1d12 hours.
14. Friendly Druid: A pod of dolphins leap from the water off the port side of the party’s vessel. One dolphin leaps up toward the deck and turns into a very damp halfling. This halfling is a Druid with the equivalent of the 4th-level Wild Shape feature. This druid has information regarding the state of the surrounding waters and some news regarding the party’s destination in exchange for some food.
15. Sale on the Seas: A merchant vessel passes by. They’re willing to do business with the party and have many general goods including rations, equipment for ship repair and maintenance, various tools, and even a few common magic items.
16. Treasure Adrift: The most perceptive party member spots a small dingy adrift in the open sea. There’s no sign of anyone aboard, but there is a single, small, locked chest shifting at the bottom of the boat with the waves. Opening the chest requires a DC 16 Dexterity check with Thieves’ Tools and within is 3d10 x 100 gold pieces.
17. Favorable Winds: Favorable winds blow at the party’s back, shorten the party’s travel time by 2d10 hours.
18. Hidden Loot: The party’s vessel passes close by a small, rocky island. The most perceptive character in the party spots a chest nestled amongst the stones. While the chest has a lock, it has long rusted and easily breaks off with a DC 6 Strength (Athletics) check or by dealing 3 points of damage to it. Within is an uncommon magic item of the Game Master’s choice.

D&D Sea Encounters: Tier 2 (5th-10th Levels)

3. Ghost Ship: Ethereal green clouds swirl above and the most perceptive character in the party spies a ghostly ship with tattered sails approaching from behind. This Sailing Ship is semi-transparent, glows a sickly green, is crewed by 1 Ghost and 8-14 Specters, and can take actions as if fully crewed. These undead creatures board the player’s vessel and attack once within movement range. If turned and not destroyed, they retreat to the ghost ship and take no actions. If all the spirits are defeated, the ghost ship vanishes.
4. Raiders from the Deep: A raiding party of 2-5 Merrow and their Giant Shark assault the party’s vessel.
5. Lightning Serpents: 1-2 hungry sea serpents (use the Behir stat block but replace their climb speed with a swim speed) emerge next to the party’s vessel. They may be sated with 3 days worth of rations (each if 2) but are extremely agitated and prone to attack.
6. Dead Waves: The sky opens up overhead and the winds completely die out for 2d12 hours, causing the party’s vessel to completely stop without the aid of oars.
7. Pest Infestation: While checking the stores, one of the player characters discovers 6 Giant Rats in the hold. They’ve eaten roughly 1/4 of the party’s rations since departing.
8. Reef Troubles: 1-2 ambulatory, sentient reefs (use the Treant stat block and give these creatures a swim speed of 30 ft.) appear directly in the path of the party’s vessel. They appear angry but not directly hostile, demanding to know what the party is doing in their ocean. If the party provides a satisfactory answer, the reefs disappear beneath the waves. If the party doesn’t abate the reefs’ anger, the creatures attack the party’s vessel.
9. Mistaken Identity: A Warship bearing the colors and symbols of a major power hails the party’s vessel. The Captain informs the player characters they’re looking for a pirate vessel closely matching the description of their ship.
10. Distressed Whale: A massive swarm of carnivorous fish (use 6-10 Swarms of Quippers) are spotted tearing into a Killer Whale a short distance off.
11. Kindred Spirits: The party’s vessel approaches a similar ship. Aboard this ship are other adventurers heading off in a different direction. They don’t have much information regarding the party’s destination and they seem kind if indifferent to what the player character’s are up to.
12. Stranded Sailors: The most perceptive player character spots a small island with smoke rising from its shores. This island is the refuge for 2d4 + 1 naval sailors (use the Guard stat block with proficiency in water vehicles) who survived a battle several days prior. They’re willing to help the player characters with sailing in exchange for passage back to their homes.
13. Golden Fish: The seas glint a brilliant rainbow color as hundreds of rare golden fish appear in the surrounding waters. A DC 18 Intelligence (Nature) check reveals these fish are inedible but they often have uses in alchemy and as other magical reagents, making them valuable to the right buyers. A handful of scales from these fish can sell for 15-30 gold pieces depending on who you talk to.
14. Helpful Dolphins: A pod of dolphins emerge alongside the party’s vessel. They seem like they’re trying to get the party’s attention. A successful DC 16 Wisdom (Animal Handling) check reveals these dolphins want the player characters to follow them. A successful DC 18 Wisdom (Perception) check reveals the dolphins are guiding the party through a section of shallow reefs, preventing the vessel from running aground and damaging the ship.
15. Art Adrift: The most perceptive player character spies a piece of floating wood with a singular crate atop it. If the players retrieve the crate and open it, it reveals a number of intact art objects totaling 1d10 x 100 gold pieces.
16. Curious Stranger: A curious Storm Giant climbs aboard the party’s vessel from the ocean. This giant wants to know about the party’s goals and quest. If they provide a good enough answer, the giant may decide to help by following the party for the next 8 hours using the control weather spell to provide favorable winds and a clear sky. Afterwards, the giant bids farewell to the party and descends back into the ocean.
17. Gale’s Blessing: A strong wind blows in the direction of the party’s destination for the next 2d4 days, doubling their travel speed for the duration.
18. Storm’s Gift: A lightning storm erupts overhead. The water becomes choppy but nothing overly threatening to the party’s vessel. Suddenly, a bolt of lightning strikes the ship. At the point of impact is a large, finely crafted shard of wood; a Wand of Lightning Bolts. (Feel free to substitute for another rare magic item of your choice)

D&D Sea Encounters: Tier 3 (11th-16th Levels)

3. Dragon Turtle Attack: An angry Dragon Turtle attacks the party’s vessel to protect its territory. The turtle may be accompanied by a group of Sahuagin for parties of 14th – to 16th-level.
4. Ocean’s Wrath: A violent storm rapidly closes in overhead; the sky blackens, the waves constantly threaten to capsize the party’s vessel, and several waterspouts erupt from the water. Staying on the deck of the ship requires a DC 20 Strength or Dexterity saving throw, a failure means getting thrown overboard into the violent ocean below. The party loses 1d4 days worth of travel time due to the storm and each part of their vessel which has hit points loses 10d10 hit points
5. Fiendish Pincers: 2-3 massive, crablike creatures (use the Glabrezu stat block but these creatures don’t have the Innate Spellcasting trait, they have a swim speed of 40 ft., and they have 4 pincers instead of 2 with no regular hands) appear from the waves, rushing toward the party’s vessel. These creatures intend to rip the vessel apart.
6. Monarch of the Seas: The most perceptive player character spots a Warship, with a Gladiator for a captain, approaching off the port side. Once within 100 feet, the Warship raises a pirate flag and fires a mangonel shot at the party. The pirate captain is willing to let the party go if they’re willing to give up any valuables they’re transporting.
7. Stormbird: The most perceptive player character spots an unusual and dark cloud off in the distance but approaching fast. A DC 18 Wisdom (Perception) check reveals a bird-like figure at the center of the cloud. This creature is a Roc with a perpetual effect equivalent to the call lightning spell, as if cast using the Roc’c Constitution score, surrounding and centered on it (additionally, the Roc may trigger the effect of this call lightning as a bonus action instead of a regular action). The Roc quickly approaches the party’s vessel but will simply bypass it unless provoked.
8. Unscrupulous Toll: A navy Warship approaches the party’s vessel bearing the markings of a major nation. The captain of this ship declares a toll of either 500 gold pieces or half of the party’s rations is required to pass through these waters.
9. Smuggler’s Folly: The party comes across an unassuming Sailing Ship. The crew of this ship act a bit weird and a DC 16 Wisdom (Insight) check reveals they seem to be nervous about interacting with the party. This crew isn’t willing to fight unless the party discovers they’re smuggling illegal goods with a DC 18 Intelligence (Investigation) check while aboard the ship.
10. Ship Battle: The party’s vessel passes by a nearby naval battle between two Warships.
11. At a Distance: The party spots an island some distance out at a cardinal direction using 1d8 (1 = North, 2 = Northeast, 3 = East, etc). For the next 3d8 hours, no matter how fast the party travels, the island stays in the exact same point relative to where they first spotted it.
12. Bloop: A deep sound reverberates from the depths. There’s no air bubbles which emerge and no unusual creatures may be sighted in the vicinity.
13. News from Shore: A Galley working as a merchant ship passes by. They have some news about the party’s destination but nothing in too much detail and are willing to trade. This ship has general goods available for sale including some mundane weapons.
14. Ocean Nomads: A group of travelers aboard wide, flat ships crosses the party’s path. These travelers have many rations they’re willing to trade and even some rare produce and other goods. They also have information on the surrounding area should the party ask for navigation advice.
15. Glittering Seas: The surrounding waters turn into a light blue-green color and sparkle in the sunlight. Despite being salt water, this enchanted water is consumable by creatures with no negative effects. In fact, drinking a least one cup or 8 ounces of this water confers the ability to breathe underwater, advantage on Constitution saving throws and Dexterity (Acrobatics), and resistance to poison and acid damage for the next 24 hours.
16. Ancient Serpent’s Blessing: The most perceptive player character notices a massive creature just below the water’s surface. A DC 20 Wisdom (Perception) check reveals the creature is probably well over 300 feet long and 40 feet in diameter at its thickest. It doesn’t appear hostile and simply disappears below the waves if attacked. If the party waits 1d4 hours, the serpent’s head rises above the party’s vessel. Softly yellow-glowing orbs emerge from the creature’s eyes around the player characters’ vessel, granting advantage on Wisdom (Survival) checks for navigation and catching fish and advantage on saving throws made against becoming frightened for the next 24 hours. This blessing also removes up to one disease or poison afflicting each creature on the party’s vessel. The serpent then submerges itself in the water, disappearing from view.
17. Mystical Fog: A thick, light-purple fog rolls in and engulfs the party’s vessel in a heavily obscured area for the next 1d4 hours. Afterwards, the vessel emerges 1d4 days closer to the party’s destination and each creature aboard the vessel receives the benefits of the bless spell for the next 24 hours.
18. Sinking Ship: The most perceptive of the player characters spots the top of a mast slowly sinking below the waves. Flotsam and debris from the sinking ship begin nearing the party’s vessel. Searching the area, the party discovers 2d6 survivors (use the Commoner stat block). These survivors claim to have belonged to a pirate crew but a mutiny led to fighting aboard the ship, resulting in an explosion which killed most the crew and damaged the ship to the point of sinking. If the party finds a way to investigate the sinking vessel, with a DC 18 Intelligence (Investigation) check, they discover a lock chest containing 6d10 x 100 gold pieces and a very rare magic item.

D&D Sea Encounters: Tier 4 (17th-20th Levels)

3. Kraken Attack: The party’s path takes them directly over the lair of a Kraken, a sunken warship the creature sunke centuries ago. Once within 6 miles of the lair, they begin experiencing the lair effects. Once they are directly above the wreckage, the Kraken emerges and attacks.
4. Souls of those Lost at Sea: An urchin-encrusted and dilapidated ship lined with massive bones appears from a sickly-green fog bank. This vessel uses the Warship stat block but its crew consists of a Lich as its captain, the officers are all Wights, the sailors and siege crew are Skeletons, the soldiers are Zombies, and the "surgeon" is a Mummy. These malevolent beings seem intent on adding the player characters and any crew aboard the party’s vessel to their undead ranks.
5. Fire at Sea: A strange, bright-orange fog forms around the party’s vessel and a small-sized Fire Elemental forms below deck and starts setting the ship ablaze.
6. Sea’s Wrath: A violent storm descends upon the party’s vessel. The effects of the storm of vengeance spell occur for the next 10 minutes, repeating effects every minute.
7. Spontaneous Whirlpool: An enormous and violent whirlpool suddenly opens up directly in front of the party’s vessel. This whirlpool is large enough to swallow their vessel whole if the party doesn’t act fast enough.
8. The Sea Goddess: A Galley approaches the party’s vessel. The captain of this ship is an Archmage and their 5 officers are all Mages. They demand the party turn over their valuables.
9. Stowaway: The most perceptive player character notices the rations are depleting faster than they should be, as if the party were accomdating another person. With a DC 18 Intelligence (Investigation) check, they discover a hiding spot below deck with a young child within (use the Commoner stat block). The child is afraid of the player characters initially and doesn’t want to answer any questions about where they came from.
10. Passive Ocean Giants: A pair of Dragon Turtles appear near the party’s vessel. They don’t seem hostile, simply out on their own in the middle of the open seas.
11. Castaway: The most perceptive player character spots a dingy bobbing in the waves. If they approach, they discover a young Commoner afflicted by the Sewer Plague disease with 5 levels of Exhausion.
12. Ocean Avatar: The most perceptive player character spies an enormous statue rising from the waters. A DC 22 Intelligence (History) check reveals this is a statue depicting the avatar of an ancient water spirit said to rule over the oceans of the world but nothing on its origin. It’s an otherwise ordinary if massive statue as it rises from the ocean floor.
13. Roaming Ice: A massive, island-sized glacier lies directly ahead of the party’s vessel. There’s nothing inherently strange about the ice other than its location. It gives off a minor abjuration enchantment if a spell like detect magic is used.
14. Moving Island: For the next 1d10 days, a small island appears and reappears in a different location relavant to the party’s vessel. It appears at a cardinal direction using 1d8 (1 = North, 2 = Northeast, 3 = East, etc), 2 miles away unless the party wishes to approach it. As they near the island, it steadily shrinks until it’s little more than a sandbar with a small chest containing 3d10 x 100 gold pieces on it.
15. Fair Winds: For the next 3d6 days, winds blow in the direction the party wishes to go, maximizing their travel speed.
16. Floating Bazarre: A large conglomeration of ships attached through loose rope bridges passes by the party’s vessel. This is a seabound marketplace with many different kinds of goods for sale from basic rations to masterworked weaponry to magic potions and even some specialty magic items.
17. Legendary Ship Wreckage: The most perceptive of the party notices a massive derelict ship, far larger than any seen before, adrift some distance off. This ship’s name seems deliberately scratched off and is entirely abandoned. Investigating the ship reveals a set of very rare magic items, one for each player character. There’s a 10% chance of one of these items being cursed but the curse is only that the item identifies as being cursed and nothing else.
18. Sea’s Blessing: A faceless, ghost-like, 30-foot tall figure appears in front of the party’s vessel. This figure’s features blow gently in the wind as they extend their arms towards the party then vanish as if blown away in the wind. Bestow upon each player character an Epic Boon from the Dungeon Master’s Guide for the next 7 days.