It’s summer - and there’s no better way to help your campaign’s heroes beat the heat than a nice, relaxing trip to the beach for some unrestrained summer fun. Of course, very little goes so smoothly in Dungeons & Dragons, which might be why the Player’s Handbook includes a section on underwater combat. For DMs looking to take their players on an aquatic adventure, here’s a quick refresher on how combat works below the waves.

The player’s handbook is actually quite brief on the subject matter, and focuses mainly on the logistics of underwater attack rolls. Creatures without a swimming speed (natural or magical) automatically have disadvantage when attempting melee attacks with anything except daggers, javelins, shortswords, spears, or tridents. Ranged attacks will also be disadvantaged (and outright fail attacking out-of-range targets) unless they are fired from a crossbow, thrown like a javelin, or the projectile is a net. Creatures and objects submerged in water are resistant to fire damage.

On the other hand, the way non-combat movement works is a little vague. Before taking the plunge, it’s a good idea to make sure the table can all agree on and understand the rules. Some DMs may require a swim (athletics) check before every movement, with tiers of success relating to how much of a character’s base movement speed they can achieve - such as a DC 5 for a third, 10 for halved, and of over 15 for most movement speed. Others might only ask that players make a single swimming check at the beginning.

Besides movement speed, there’s also vertical movement - underwater, everyone has a more 3D playing field. Some DMs will allow a bit of vertical movement as flavor text, others may factor it in more seriously and take exact distance into account. It’s all up to preference, since it isn’t clarified in the Player’s Handbook.

Now, as one might imagine, the base rules in the Handbook mean that a lot of attack types will be made at disadvantage. Worse still, spells with a spoken component may not be available if the sorcerer can’t talk. Coupled with the fact that most of your player characters probably can’t breathe underwater naturally, the next step seems somewhat clear: players need a way to prepare themselves for this type of occurrence. If they know there’s a good chance that they’ll be making a dive, it’s a good idea to have their next trip to the alchemist include a few water-themed potions in stock.

There are also spells to get the same effects: Alter Self (Aquatic adaption), Freedom of Movement, and of course, Water Breathing, among others. Water Breathing is ideal for parties, as it can be cast on up to 10 willing creatures and lasts a full 24 hours. Depending on DM discretion, it may also make it possible for underwater speaking as well, putting spoken-word spells back on the table. What it doesn’t do, however, is lift the movement restrictions imposed by being underwater. Assuming your players don’t have a natural swim speed or access to a potion that grants swim speed or freedom of movement, that means they’ll likely be attacking at disadvantage.

So what’s a party to do? Get creative. Even while underwater, the other aspects of combat apply: so the party should get to work on ways to disadvantage the enemy or give themselves advantage (thus making their attack rolls neutral). It’s still possible to flank enemies, grapple them, blind them, or use spells like True Strike. And maneuvering underwater to flank isn’t as complicated as it might seem. In water, everyone will have the option to go above, below, or around each other (although it’s still wise to mind attacks of opportunity).

By manipulating the various means of gaining advantage in normal combat, clever players can get around some of the underwater attacking restrictions in the Player’s Handbook, even if they can’t grant themselves magical movement speed. It also encourages a lot of tactical thinking that’s sure to make the battle a memorable one.

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