Last Updated on January 22, 2023
When most of us think of D&D, we envision the exploration of old, underground ruins or a network of rocky caverns.
However, there are also some creatures iconic to D&D that live in the water. Sahuagin, water weirds, and even black dragons can live in the depths of the sea.
That means that, throughout your character’s career, they will come across an aquatic challenge at some point.
If you want to make sure you swim rather than sink, then let’s take a look at the rules and guidelines for swimming and underwater combat.
Movement types in D&D aren’t limited to just walking or running. If you want to traverse water, swimming is the default option for most creatures.
On page 182 of the Player’s Handbook, there’s a section called Climbing, Swimming, and Crawling:
“Each foot of movement costs 1 extra foot (2 extra feet in difficult terrain) when you’re climbing, swimming, or crawling. You ignore this extra cost if you have a climbing speed and use it to climb, or a swimming speed and use it to swim.
At the DM’s option, climbing a slippery vertical surface or one with few handholds requires a successful Strength (Athletics) check. Similarly, gaining any distance in rough water might require a successful Strength (Athletics) check.”
In other words, when your character goes swimming without a swim speed, they will move half as fast as they would on land.
You still have the option to take the Dash action, which would get you up to your normal speed.
However, you lose your action to do this, so you won’t be able to attack or use any items.
What’s interesting about these movement rules is that there are no other rules in the Dungeon Master’s Guide or any other book for that matter.
Many players believe that heavy armor or heavy characters have a harder time swimming, but that’s only the case if you’re carrying too much gear before you jump into the water.
D&D 5e has done away with a lot of the complexity from previous editions, for better or for worse.
Ways To Get Around Swimming
There are ways to get around swimming if you look for them. These could be useful for quickly solving a water-based puzzle, or if you need to traverse a large body of water for your adventure.
Here are some workarounds from the Player’s Handbook:
- Water Walk Spell: This third-level spell for Clerics, Druids, Rangers, and Sorcerers lets you walk on water like it’s a solid surface. It’s a ritual spell that affects up to ten willing creatures, so it’s a resourceless way to get your whole party across the water.
- Wild Shape: Druids of fourth level or higher can turn into creatures with a swim speed, allowing them to swim much faster than in their humanoid form.
- Buy A Boat: Most waterborne vehicles from the Gear chapter are expensive, but rowboats go for 50gp each. Three or four of these could ferry your party across a body of water and would give the stronger party members a chance to shine with an oar and some high Athletics checks.
It’s also worth mentioning that flight can help you avoid swimming as well. There’s no need to swim if you can instead soar above the waves!
This is the reason why you don’t want to mess with the water unprepared. Most player races in D&D don’t have a way to breathe underwater, so the risk of drowning is a real possibility while adventuring in aquatic environments.
Here are the rules about suffocating from the Player’s Handbook:
“A creature can hold its breath for a number of minutes equal to 1 + it’s Constitution modifier (minimum of 30 seconds). When a creature runs out of breath, it can survive for a number of rounds equal to its Constitution modifier (minimum 1 round).
At the start of its next turn, it drops to 0 hit points and is dying. For example, a creature with a Constitution of 14 can hold its breath for 3 minutes. If it starts suffocating, it has 2 rounds to reach air before it drops to 0 hit points.”
Since most adventurers are packing a positive Constitution modifier, this means that many adventures can last for a few minutes underwater before needing to take a breath.
This could be enough for exploring a small lake, but it’s not enough for diving to the bottom of the ocean. This means you’ll need other methods to get down there!
How to Avoid Drowning
Since nobody wants to drown, it’s best to avoid that possibility, to begin with.
Here are some ways to prevent your character from drowning:
- Water Breathing Spell: This third-level spell for Druids, Ranger, Sorcerers, and Wizards lets up to ten willing creatures breathe underwater for eight hours with no concentration. As a ritual, this is a surefire way to give your team a way to breathe underwater for the day.
- Turn Into Amphibious Creatures: Whether through the druid’s wild shape ability or the polymorph spell, turning into a creature with the amphibious trait would let you breathe underwater. Frogs and crabs are good examples of these kinds of creatures.
- Boost Your Constitution: Increasing your Constitution through magic items or ability score improvements will let you spend more time underwater. This way, you have more room to work with when diving below the depths.
Options to avoid drowning are slim in the Player’s Handbook. In general, the best way to avoid drowning is to find a way to not be underwater for too long in the first place.
You don’t have to mess around with these rules or safety measures if you don’t go underwater much in the first place.
Nothing in a D&D adventure is ever easy, and that includes underwater exploration as well.
All sorts of monsters lurk in the depths in the D&D multiverse, so you will come to a point in an aquatic adventure where monsters attack.
The mechanics of running combat underwater aren’t too different from normal, but there are some special rules to consider when engaging in underwater combat.
Weapons and Armor
Although armor isn’t a concern by normal rules, weapons work differently when you are underwater.
Melee weapon attacks are much more restricted when you are underwater. Creatures without a swimming speed make their melee attacks with disadvantage while underwater.
The swimming speed could come from either a natural or magical source to count.
Also, this rule doesn’t apply if the creature is attacking with a dagger, javelin, shortsword, spear, or trident.
Ranged weapon attacks aren’t much better underwater. While underwater, attacks with ranged weapon attacks have disadvantage when used at their normal weapon range, and automatically miss when used up to their long range.
This means that firing a shortbow with a range of 80/320 underwater is done with disadvantage for the first 80 feet, and then misses at anything beyond that.
Like with melee weapons, certain ranged weapons don’t suffer this penalty. Crossbows, nets and thrown weapon attacks aren’t affected by this restriction.
Casting spells underwater doesn’t have any restrictions on it based on the rules from the Player’s Handbook. The Dungeon Master’s Guide doesn’t have any extra insight, either.
In fact, Jeremy Crawford, one of 5e’s lead designers, has mentioned before that being underwater doesn’t prevent spellcasting.
However, another tweet from Crawford clarifies that being underwater doesn’t prevent casting a spell with verbal components, but that talking means you aren’t holding your breath.
The implication here is that, once you speak to cast a spell with a verbal component, you are no longer holding your breath and start counting down the rounds before you start suffocating.
Since Crawford’s tweets aren’t official rules, underwater spellcasting falls into the realm of DM fiat. If you want to play a spellcaster in an aquatic campaign, talk to your DM and see what they want to do about rules for casting underwater.
Also, for you spellcasting firebugs out there: beware that creatures fully submerged in water are resistant to fire damage.
Try to get your foes out of the water, or use a different spell, if all your targets are submerged.
Unconsciousness While Underwater
If the worst-case scenario happens and you’re knocked out underwater, this is bad news. Since an unconscious character is unable to hold their breath, that character would start counting down rounds before they are suffocating.
If one of the creature’s allies can heal them somehow, then everything is fine.
The problem is if the creature starts suffocating after its rounds have elapsed. According to the suffocating rules, the creature drops to 0 hit points and cannot regain hit points until they can breathe again.
Basically, if your buddy goes down underwater, get them back up and healthy as quickly as you can!
If you wait, you might not be able to heal them without getting them out of the water first.
Homebrew / Alternative Rules
The totality of the underwater combat and suffocating rules take up less than half of a page in the Player’s Handbook.
For keeping the game simple, this rules-light approach is great. Still, some DMS, especially veteran DMs, might want more substance for underwater rules.
These rules also don’t do much to inspire epic adventures on the high seas since the only added danger is the suffocation.
So, if you want to add some drama to the underwater combat rules, here are some ways you can spice thing up:
Heavy Armor Sinks
One of the main ways some DMs spice up aquatic adventures is by making armor matter to your swimming capability.
The idea here is that, when characters wear heavy armor, they aren’t as mobile in water as someone wearing light or no armor.
Wearing heavy armor could mean that you are always making Athletics checks to stay afloat, or to even move at all.
Falling Into Water
Falling into the water is another strange gap in the rules for D&D 5e. Falling is treated the same regardless of what kind of surface you’re falling into, meaning landing in water is just as damaging as landing on the ground.
For short falls, some DMs might allow players to make an Acrobatics check to reduce their fall damage when landing in water.
Others might treat falling into the water as 10 or 20 feet less height for the damage roll, as long as the player could also sink that far into the water.
Being Underwater Hampers Spellcasting
Casting spells underwater remains a strange subject despite the clarifications from Jeremy Crawford.
Those rules might not sit well with some DMs since almost anyone who has gone swimming before knows how hard it is to hear underwater.
When you try to talk underwater in reality, it’s impossible to understand what the other person is saying.
Since the narrative of spellcasting in D&D is based around clearly heard and defined words of power, being able to cast a spell underwater despite the words being garbled doesn’t make a lot of sense.
Some DMs will just prevent spellcasters from casting a spell with a verbal component underwater because of this.
Others might require a concentration check to make sure that the player can focus on the words of power despite being underwater. Either of these changes would introduce the physics of the real world to the situation.
Summing It Up
The swimming and drowning rules in D&D 5e don’t see much use since aquatic adventures aren’t very common.
However, a DM looking to challenge their party could use these rules to introduce a different way of thinking to their players alongside new challenges.
These rules aren’t very long, so they’re easy to digest and use at the table.
However, the underwater rules don’t answer every question. Players will have to work with their DM to make decisions on how the rules are interpreted, and if the DM wants to use a homebrew ruleset to keep things moving or realistic.
Overall, underwater combat introduces another layer of fantasy to a D&D campaign.
As long as the players are having fun with the new environment, that’s what ultimately matters.
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Rich is an avid D&D player and DM. He has been playing since the Advanced Dungeons & Dragons 1st and 2nd editions. He has run campaigns of various editions with family and friends for over 20 years. Playing DnD 5th Edition in person at local game stores and online with VTT’s over the past 10 years has provided a consistent connection to how the game has grown. He strongly believes in understanding the source material, but catering the games to your individual players. Feel free to ask anything in the comments or drop him an email: [email protected].