10 Underwater Challenges for Adventuring Parties
Ah, the call of the ocean! There’s nothing quite like submerging your adventurers into the briny depths, where every shadow could be a tentacle, and every bubble could be your last. Underwater campaigns are like that annoying coworker who always eats tuna salad—challenging, unforgettable, and filled with questionable surprises. Here are ten creative underwater challenges to help you sink (or swim) in your next campaign.
Now, let’s dive in!
1. Breath of Life
Securing air underwater is critical. Pose this challenge by limiting spellcasters’ access to water-breathing magic or incorporating temporary oxygen sources like potions or enchanted pearls. Add tension with rapidly depleting resources or an unexpected attack.
Expanded Details: Breathing isn’t just about magical solutions. Incorporate environmental factors like hidden air pockets, plants that exude breathable oxygen, or mechanical devices that require maintenance. A sudden current knocking a character's respirator loose can escalate the danger.
DM Tip: Use mechanics like exhaustion for characters running out of air. Introducing air pockets within ruins can provide relief and a tactical advantage. Consider adding countdowns to increase urgency and encourage fast decision-making.
2. Blinding Depths
Underwater environments often suffer from poor visibility. Creatures and hazards may lurk just out of sight, creating suspense and surprise encounters. Use magical or bioluminescent flora to light the way—or lure players into danger.
Expanded Details: Introduce glowing schools of fish or mysterious orbs of light that might guide or mislead players. Pair poor visibility with ambient sounds of unseen creatures to create tension.
DM Tip: Adjust combat mechanics for limited sight, such as imposing disadvantage on ranged attacks. Include perception checks or light-based spells as essential tools for overcoming the gloom.
3. Pressure Points
Exploring deep ocean trenches comes with the risk of crushing water pressure. Characters might need special suits, spells, or a gradual descent to survive. This adds a layer of preparation to the adventure.
Expanded Details: Pressure can be represented by gradual Constitution checks or environmental effects like slowed movement and penalties to spellcasting. Specialized equipment might need repair after prolonged use.
DM Tip: Introduce pressure resistance checks. Failures could lead to health penalties or gear malfunctions. Include narrative elements, such as a collapsing tunnel or bursting air bubble, to keep players on edge.
4. Currents of Chaos
Strong underwater currents can carry players off course or split the party. Currents might lead to undiscovered locations or treacherous traps, adding unpredictability.
Expanded Details: Currents can drag players into caverns, against sharp coral, or towards hostile territories. Provide opportunities for players to anchor themselves or use creative solutions like spells or tools to counteract the flow.
DM Tip: Use random rolls to determine where players are swept. Tie in treasure or unique encounters as incentives. You can also use currents as obstacles during combat, adding depth to tactical planning.
5. Silent Predators
Marine predators like sharks, krakens, or sahuagin patrol underwater domains. Silent and stealthy, these enemies strike when players least expect it.
Expanded Details: Predators may use ambush tactics, camouflaging among coral or kelp. Include signs of their presence, like distant shadows or the remains of a recent meal, to build suspense.
DM Tip: Create an encounter where players must hide or outmaneuver a massive predator instead of fighting it outright. Use stealth mechanics or lure mechanics to add variety to the gameplay.
6. Lost in Translation
Communication becomes difficult underwater without proper tools. Gestures, light signals, or magical means like telepathy are necessary. Miscommunication could lead to mistakes or delays.
Expanded Details: Have NPCs or even enemies use their own unique underwater sign language. Misinterpretation could cause complications, like offending a local tribe or misunderstanding directions.
DM Tip: Use this challenge to encourage creative problem-solving. Reward players who roleplay their communication solutions. Introduce magical or mundane artifacts that facilitate understanding, such as conch shells that amplify speech.
7. Treacherous Terrain
Underwater ruins, shipwrecks, or coral reefs create dynamic battlegrounds. Dangerous terrain, like sharp coral or entangling kelp, complicates navigation and combat.
Expanded Details: Collapsing structures, unstable treasure piles, or predatory plants can add layers of danger. Have traps designed to take advantage of the water’s movement and buoyancy.
DM Tip: Introduce environmental hazards with saving throws for damage or movement restrictions. Include interactive terrain, such as ropes or magical levers, that players can manipulate to gain an advantage.
8. Magical Maelstroms
Incorporate underwater magical phenomena, like portals that randomly teleport players, geysers of boiling water, or zones of antimagic. These elements can disrupt carefully laid plans. You could even alter spells to better reflect the underwater condition. Such as, fireball becoming an explosion of boiling water. You can learn more about underwater combat from our full podcast episode covering Underwater Combat.
Expanded Details: Magical maelstroms can serve as both hazards and opportunities. A portal might lead to a treasure-filled grotto or a deadly plane. Boiling geysers can also act as environmental triggers to reveal hidden areas.
DM Tip: Use maelstroms as puzzle elements, rewarding clever strategies for bypassing them. Players could use timing, specific spells, or even creature interaction to navigate the phenomenon.
9. Aquatic Armory
Standard weapons and armor don’t perform well underwater. Players must adapt by finding or crafting specialized gear, like harpoons or enchanted swimsuits.
Expanded Details: Introduce the concept of rusting or damaged equipment. Let players craft items from underwater resources, such as enchanted coral or sharkskin leather, to personalize their gear.
DM Tip: Introduce vendors or quest rewards for water-friendly items, encouraging exploration. Add unique magical weapons that function exceptionally well underwater but have drawbacks on land.
10. The Siren’s Song
Enchanting underwater creatures like sirens or merfolk can beguile adventurers, leading them astray or into traps. Combine charm effects with environmental hazards for a multi-layered challenge.
Expanded Details: Sirens could compel players to follow them into whirlpools or collapse fragile ruins. Use their songs as both a lure and a warning for greater narrative depth.
DM Tip: Create moral dilemmas by having these creatures plead for help or claim ownership of an area players seek to explore. Use Insight or Deception checks to keep players guessing about their true motives.
Concluding Your Aquatic Adventures
Congratulations! If you’ve made it this far, you’re either a daring adventurer or a DM who just rolled a natural 20 on patience. Underwater challenges offer a smorgasbord of story-rich opportunities—and maybe an existential crisis or two for your players. If you don’t want to create your own, consider picking up The Dark Tides of Damodan. This adventure includes many of our tips here and will provide a great mystery adventure with a tight time line. This is a great way to delve into underwater adventures and support me and my work.
The Dark Tide of Damodan - Underwater 5e Adventure
A mysterious disease is killing off locals and visitors alike in the port town of Havenword. While the adventurers are in town, Havenword is attacked from the sea by nasty fish-headed creatures. After the battle the characters learn that the creatures dragged off several townsfolk. They have been tasked with finding the captives and returning them safely. The only problem...they were taken out to sea.
The characters must delve into the depths of an underwater keep to rescue the captives. Using the knowledge of the captives to help locate one another, all the while, avoiding the sinister Damodan's forces. Will the characters turn the tides in their favor? Or will they swim with the fish?
So, throw on your enchanted swim trunks, pack a waterproof spellbook, and dive headfirst into the deep! Just remember: in the ocean, no one can hear your warlock scream. Happy adventuring!
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