Underwater / Sea based Campaign


Pathfinder First Edition General Discussion


Hey all. I was toying around with the idea of making an underwater/sea based campaign. I was wondering if anyone has done so before me, and could thusly contribute any bits of helpful information.

I am thinking that the PCs would start out above water, maybe on ship-based missions or somesuch. And then when the time came for them to go underwater, I would have the PCs' allies supply them with basically a magical water-breathing apparatus to make their lives a little easier. (Better hope they don't run into any antimagic fields in the deeps...)

My only concern is that their mobility would be a severe handicap when their swim speed (assuming medium-sized PCs and a successful swim check which would be 1/4 or 1/2 land speed) is rather inadequate against the underwater beasties they would be up against. Sahuagin rangers with bows and shark companions, I'm looking at you...

On the other hand, I think that the heavy penalties on slashing/bludgeoning weapons underwater sort of forces them to pick from a rather small list of piercing weapons. This is both good and bad in my opinion. Good in that it is sort of like munchkin repellant and allows less-than-popular weapons to have a bit of spotlight, bad in that it can shut down some character concepts.

Any tips or suggestions?


I've got one. Check out Sunken Empires. It takes exactly that approach to aquatic adventures, giving level-by-level breakdowns for getting PCs' feet wet as they advance in levels, and even provides a great little environment to facilitate those sorts of adventures. Perfect for what you want to do...


Sunken empires is very cool. So cool that I can't wait for frozen empires to come out


I'll pick it up once I get a source of disposable income.

Meanwhile, I'm gonna make me a sahuagin ranger. *evil grin*

RPG Superstar 2012 Top 32

Kryptik wrote:

Hey all. I was toying around with the idea of making an underwater/sea based campaign. I was wondering if anyone has done so before me, and could thusly contribute any bits of helpful information.

I am thinking that the PCs would start out above water, maybe on ship-based missions or somesuch. And then when the time came for them to go underwater, I would have the PCs' allies supply them with basically a magical water-breathing apparatus to make their lives a little easier. (Better hope they don't run into any antimagic fields in the deeps...)

My only concern is that their mobility would be a severe handicap when their swim speed (assuming medium-sized PCs and a successful swim check which would be 1/4 or 1/2 land speed) is rather inadequate against the underwater beasties they would be up against. Sahuagin rangers with bows and shark companions, I'm looking at you...

On the other hand, I think that the heavy penalties on slashing/bludgeoning weapons underwater sort of forces them to pick from a rather small list of piercing weapons. This is both good and bad in my opinion. Good in that it is sort of like munchkin repellant and allows less-than-popular weapons to have a bit of spotlight, bad in that it can shut down some character concepts.

Any tips or suggestions?

If they have a wizard in the PC's group, maybe drop in a captured spell book with some useful spells for under the sea: fly (boosts speed underwater too!), breathe water, freedom of movement, etc. The wizard can then make scrolls or wands of the spells they need to function down there.

Scarab Sages

I ran a short underwater campaign in Forgotten Realms during 2E years, using the Sea of Fallen Stars book and a series of Sahaugin based adventures, whose names mostly escape me now (Night of the Shark I think was the 2nd one). If you can get your hands on them, especially the Fallen Stars book, I highly recommend them, since they had a lot of adventure hooks, territorial writeups, etc.

It was a lot of fun, and I think the players enjoyed the change. I know they were a lot more scared, simply because underwater is a hostile environment, and you cant see whats sneaking up on you. I eased them into it in stages, since the latter half of the game was completely aquatic.

1. Party on an ocean voyage, carrying an important cargo as couriers.
2. Pirates attacked and took their ship, leaving the crew alive on an older salvaged ship that was damaged. They had to brave ocean encounters on a leaky, damaged ship for a bit.
3. Party hired to go after pirates, find out their boat was sunk.
3. Original employers offer cash and some water breathing magic and hire the party to recover their treasure
4. Move on to more and more underwater adventures, including exploring and living in sunken cities.

Or you use Sunken Empires and just have them go directly to exploring an underwater city/ruin :)

Sea to Shore I would also highly recommend for underwater adventuring.


I'm running nautical/under water campaign right now, using Sunken Empires as a source book, alongside some other stuff (stormwrack, Oriental Adventures, etc). The primary issues you ruin into are

1. Swim speeds.
2. Breathing under water.

For one I added a 30ft swim speed to 1/2 Elves to make them 1/2 Sea Elves, and made it so everyone has swim as a class skill.

for the second, you just have to wait until the casters can throw multiple 3rd level spells around, OR provide them with a Bottle of Air.

The weapon thing is kinda hit and miss, since they spend as much time on land (islands) and exploring under water. BUT my big hitters are using rapiers and short swords, so they do fine.

Just need to stop eating party members with harks. They get so testy :)

Grand Lodge

What I do, that's not yet been mentioned, is make maps a bit differently.

Make a regular mountainous + hilly + forest + plains map, as specific as you'd make it for an overland, wilderness adventure, then color it with different shades of blue, indicating depth. Thus, instead of a surface map, which is pretty lame, you have a floor map.

Anyway, that's what I do: make a map with a handful of small islands surrounded, not by endless blue, but an equally detailed terrain map between the islands.


I would take the concept to it's fullest and make the characters underwater races, and move the adventure towards an epic encounter on land at later levels. In addition to W E Ray's suggestions do some basic research on ocean geography, currents, etc.

Some example links are provided below and you local library is a good choice.

http://www.nature.com/news/2001/010111/full/news010111-6.html

http://www.waterencyclopedia.com/Mi-Oc/Ocean-Biogeochemistry.html

Just like civilization on land, there would be major activity next to easy transport currents, whether for hunting/gathering, or moving resources. Or some may be bottom feeders ... gasp!

Also consider 3D combat being the norm, or at least easier, including restrictions on movement as appropriate. I would skip the pressure affects on land lovers.


As far as adapting rules from other editions, Stormwrack and Necro's Dead Man's Chest go for nice prices on the used market.

A spell that grants a swim speed for a reasonable amount of time should probably be a 1st- or 2nd-level spell. PCs might also want to invest in a cloak of the manta ray, or one of the more exotic forms of lycanthropy.

The real problem is pressure. 1d6 crushing damage per minute per 100 feet of depth. That can get bad quick once you get too far down.


Pathfinder Adventure Path Subscriber

I can't find the title for it, but there's a Red Box D&D supplement that always stood out as one of the better ones, with the understanding that you have to super-adapt everything.


"The Blue Planet" is also a great BBC nature series.

If you want a highly realistic marine environment, you should decide whehter the environment is warm enough for coral, or whether there is instead kelp forests. Or have both, it's a fantasy campaign ;)


The first edition 'U' series would be a great start. At low levels, you deal with mararauders from the deep. As time goes on, you go to them, and there are really cool underwater dungeons to explore.

You may want to tell the players that this is an aquatic campaign, and they will be above and below the surface, before character creation. Otherwise, it might feel like "guess what, now every monster can FLY, and EVERYONE is faster than you, and has better senses. Super fun, right? Oh, and did I mention your weapons don't work?"


Thanks for the info everybody, keep it coming!

Here are the main restraints I foresee...

1) Breathing
2) Swim speed
3) Weapon limitation
4) Vision limitation
4) Pressure crushing damage
5) Cold damage
6) Ineffective fire spells

Having a caster will obviously help these issues, but in case the PC lineup does not include a caster I will probably have to hand out items to keep the game fun. In fact, even if they do have a caster I'm thinking that if the game is going to spend a significant amount of time underwater I may want to hand them out anyway, just because the caster will feel like he/she is sacrificing spells that are meant as once-in-a-while utility spells to be on hand all the time just to get by.

I will probably have #1 and #2 be covered by items, and all the rest will have to be situational. I will likely allow Merfolk/Sea elves/half sea elves as playable races with swim speeds so they won't need the swim part of the items. Since action will take place both above and below water, the weapon limitation shouldn't be too bad. Slashing/bludgeoning weapons above and piercing below. I feel like there is a diverse enough selection to work. I am leaning toward allowing a lot of the fire-based spells to do another kind of elemental damage.

Oh and yes, I will make it very clear to the PCs what sorts of challenges they will face.


Don't forget that now every combat will be completely 3D and opponents can attack from every conceivable angle, including from below if the battle doesn't take place on the ocean floor. Also, if the campaign takes place in the deep sea there may well be absolutely no light to speak of. Darkvision only goes out to 60-120 feet so imagine being totally blind and surrounded by absolute darkness past 120 feet ahead of you. I would imagine many creatures would simply pass one another up at fairly close distances and not even know the other was there. This is amplified by the fact that swimming really doesn't make much sound so everyone is essentially moving in stealth. This of course gives an obscene advantage to creatures like sharks and the like who rely on scent to find prey. The ocean is a freaking scary place and can be a nightmare to run a campaign in. I've attempted it and it didn't go so well.


So based on what dork lord stated think of some of the items that are common in underground campaigns, like glowing lichen and substitute what is appropriate. Set a depth level as the norm, perhaps stay within 500 feet with plenty of undergound ravines and/or mountains. You can also use ruins, like ancient merfolk cities and instead of having aquaducts, make provisions for bringing in air tunnels. This may even include light to grow plants, etc.

And of course you can use creatures like lantern fish to lure the unsuspecting.

One of my first campaings was a underwater one, that I had planned out, with underground rivers of moving mud, coral reefs, ancient ruins, etc. To bad I left if at school and never found it again.

One more adventure plot is to have an ancient merfolk shaman approach the adventurers for help after a ship wreck, or something similar, and the characters can be granted an item to allow breathing under water.

Another concept that came to mind is a shipwreck containing warforged that drops to the bottom of the ocean. Since I am considering an eberron campaign, I may go with that one.


Um, just adding something of note.

You could always re-work an existing feat to give players a helping hand.

Take for example "Shingle runner" from Curse of the Crimson Throne" adventure path.

Feat: Shingle Runner; Grants a +2 bonus to Climb and Jump checks and allows user to take Climb checks even when distracted. If they fall, they reduce the total damage taken from a fall by 1D6

I just swapped some words around and came up with this,

Feat: Wave Rider; Grants a +2 bonus to Swim and 'Dive' checks and allows user to take Swim checks even when distracted. If they fail, they reduce the total damage taken from a (Um, well *scratches head* ^^;) by 1D6

Um...yeah...well...I still haven't figured out a good use for the 'bounce when you fall of a roof' aspect of the thing, but you get the idea.

Also, for adventures taking place in the 'shallow' end of the ocean. Say along a coast and such, you could/can also allow the feat that extends how long a character can hold their breath.

Of course this may also seem to be a mite 'feat' intensive, but as the Dm you can 'wing' how many and what types of starting feats people get. ;)

Also there is/was "Water Adaption" Feat printed in the "Stormwrack" book and in the Golarion Campaign guide there's a Feat called "Spirit of the River" which allows an aquatic character (Monster? ;) ) the ability to remain out of water for one day per Constitution Bonus.

Just some more thoughts and ideas. (^_^)

Scarab Sages

Dork Lord wrote:
The ocean is a freaking scary place and can be a nightmare to run a campaign in. I've attempted it and it didn't go so well.

Having run an underwater adventure prior to trying my hand at the longer campaign, I confess the earlier adventure did NOT go well at all. There was no scariness or mystery to the underwater aspect, since I "provided" the players with plenty of water breathing and movement magic right off the bat. Also, I neglected to emphasize the pressure, lighting, and coldness issues, with all add to making the players feel more vunerable.

Balance is the key here. You want your group to desire adventuring underwater, for whatever motivating reasons they have, but also to fear it somewhat and be nervous when attempting it, at least initially. I think it is highly important during the first outing submerged to either not provide enough magic to cover water breathing, or make it timed, like potions, so they have to pay attention to lack of air issues. Likewise, emphasize their clumsiness underwater when fighting things like sharks, sahaugin, etc, who are native to this environment. Just because characters can breathe water, doesn't mean they suddenly become human fish! :)

Later adventures should be deeper, where pressure and lighting are issues, so that even when they can move and breath with no fear, other facts enter into the equation. Plus, now they are going where the big boys live, the really scary underwater dwellers, both brutewise and magic using.

Just tossing my 2 cents out there, for those considering this because the two things that caused problems for me the first time around were not having a strong enough party motivation to keep at the underwater aspect, and not emphasizing the strangeness and hostility of the sea. One last note, I did make a point to also emphasize how beautiful the coral beds, sunlight in the shallows, etc were, to contrast to the deeper ocean.


1 person marked this as a favorite.

May I suggest a more organic approach to land-based races going under-water? In an old Dungeon/Dragon magazine, there was a symbiotic parasite that enabled the Locathah cultists of the Plague Goddess of 3.5 to exist permanently out of water. Reverse-engineer that into Necklaces of Water-Breathing as Organic Symbiotic Parasites that attack around a characters neck, burrowing into the flesh with tendrils that twine around the character's blood-vessels. Take a Necklace of Water-Breathing (3x5x1,800 = 27,000 gold) and turn it into a 3HD Abberation or Magical Beast that is untargetable while worn except during Grapple attacks, take a few hundred or a thousand off the cost because the creature drains the wearer, netting the wearer a -2 to Constitution so long as the Parasite is worn due to the drain on their blood-supply by the Parasite's feeding.


There was something similar in the TSR "Sea of Blood" module, explained as the ancient biotechnology of the anguillians.

Of course, by the time they found that stuff, the party had basically gone through the entire Monstrous Arcana sahuagin trilogy.

Community / Forums / Pathfinder / Pathfinder First Edition / General Discussion / Underwater / Sea based Campaign All Messageboards

Want to post a reply? Sign in.