Site icon POCGamer

Going Aquatic Part 3: World Building

It’s #AquaticSummer and I’m loving writing these posts! People know I love my world building, and now it’s time to dive into the complexities and considerations of creating an aquatic setting. The cool thing here is that a lot of this guidance borders on being genre agnostic, so let’s go!

Concept and Scale

This is the first place where things get different. Are you creating an entire world? An archipelago? An undersea canyon? A river and its delta? Any of these concepts are going to affect the scope you’re working at. An undersea canyon, for example, might seem large at first; but is actually a fairly confined space you can work with, meaning you can increase the amount of detail in each location there. Whereas a river and its delta seem simple at a glance, but in reality? You’re looking at multiple islands, sandbars, flow directions, tidal considerations, and then the surrounding landmasses. So your scope for detail goes down.

Like any world building, I always recommend you look at how much you need to create to get things going and what you can develop later. When you’re working on something with as many moving parts as an aquatic area, this is even more important. Not only do you need time to do the world building, but as a GM, you may be creating some extra material to help get your players up to speed. Once you have your concept, be honest with yourself about the scope you need to achieve and what you can actually achieve.

Understanding the Water

Ocean, lake, sea, river, surface or subsurface, you need to be familiar with what’s up. And by that I mean, you need to have at least a cursory understanding of things like currents, tides, depth, and so on. Why? Because unlike telluric world building, these things have a very real impact on the conditions the players will be navigating their characters through (no pun intended). Currents aren’t just “like the wind but in water” (someone actually said that to me once). Tides are a vital cyclical event that, depending on the high and low tide marks, can radically alter a shoreline and what the players can do there. Depth is a thing because dropping something, or someone in the water could be as minor as the subject getting mildly wet or needing deep water rescue.

So you’ll need to take a bit, maybe do some reading or watch a few videos, and get a lock on things. Because that’s going to make a world of difference when your players hit the ground. And again, this can aid you in anchoring your players so they know what’s up and can interact with the setting in ways that make sense.

Getting Around

Oddly, this part comes before getting down and dirty with other nuts and bolts of your world build. Why? Because this is going to directly affect how you layout the setting. Are they on seadoos or the fantasy equivalent? Submersibles? Are they big ones or individual ones? Is there a mothership or tender? Do you need a big ship or can small vessels and boats do it? Why ask all this now? Because it’s going to inform you map design. If it’s a mega-yacht, then there needs to be space for said mega-yacht. If it’s underwater, do they have some kind of dive gear, and what limitations do their submersibles have? Are there places it can’t go? What can go there?

Between this and the two previous considerations, you’re now set to start mapping!

Plotting it Out

This is a unique space where you are literally mapping both the environs the player characters will be in and the story to a greater degree than normal. Aquatic settings and storylines mix easily and the latter is a significant influence on the former. Two big things here are to make sure it doesn’t feel like a railroad (add extra areas with real meaning and value), and to keep the water in sight. That latter point is the keystone of aquatic campaign mapping. There should be few if any locations that are not within eyeshot or at least binoculars distance from the water. The water isn’t just a medium for travel here, it’s a thematic element in of itself. That can be very easy to lose though, so it needs to stay in focus, or at least immediately adjacent to what’s happening.

Once you’re mapping, you have a new thing to consider too. Remember depth from earlier? That’s extremely important here. Even if the plan is the player characters never see anything but the surface, depth is still important. Depth helps determine what monsters or creatures they can encounter, where they can go and how they can get there, and more. Likewise, for places with tides that are exceedingly high, you may need to make a few sets of maps to reflect the shore when the tide is out or in. And again, remember the Getting Around part. Boat and ships aren’t cars or horses. There are space requirements for dock facilities if you’re using a port, or there needs to be a moorage plan. Like I said, lots to consider with the world building here!


This is where things get AMAZING. Why? Because aquatic campaigns are a borderline carte blanche to go wild with monsters, creatures, and all that good action!

Foremost, you get to layer up your critters. Aquatic settings have depth as a factor, meaning that there’s literally layers of different critters below the surface. And some can move between layers. This means you can vary the threat levels and challenge levels with verticality. And then there’s the cave/cavern/hole options, which can have whole different micro-ecosystems of critters.

But it’s not just critters in the water, they’re in the sky too! Aerial threats are a big thing over water, and in a world with big water critters, you’re likely to get big ones in the sky too. And big things in the sky may, occasionally, see player characters as entirely viable food sources. Or as shiny things to add to their nesting areas. Or as gifts to mates. The point here is that “aquatic” doesn’t limit you to putting critters in the water.

Next comes the telluric critters. These are what you’ll have on shorelines, roaming the banks of rivers, occupying islands, and on the exposed parts of wrecks. The recommendation I have here is to not miss out on the potential of amphibious critters. Critters that can transition between land and water are loaded with potential, use them! And good old-fashioned land-based critters are a nice change of pace to throw in too.

As a final note in this section, I’ll say what I have said before: mix it up. The real world’s waterways are all very different. Do the same with your setting. Avoid that same-y feeling that can happen by overusing the same critters over and over. This always helps things to stay fresh and keep the players interested.


By this point you’ve got a map, critters, know how the players will be getting around (at least initially), a story idea, and at least a cursory knowledge of how aquatic stuff works. It’s time to work on the peopling of the place. Now, I’m going to dive into that in the next post, but what you need to do at this point is work out the broad background guidelines for the setting. Ask questions like:

How did the setting get the way it is? Was it natural? A cataclysm? Some kind of accident?

What peoples are around the setting? How did they get there? Did something happen to other peoples?

Where do the people fit into the ecosystem? Are they its masters? Do they co-exist? Are they encroaching on the territory of critters?

When are the effects of seasonal changes felt and what are they?

Why should the players be invested in this, and more specifically, what things in the setting will grab them?

Who in the players will need the most anchoring to lay a baseline for this setting? And once you’ve identified this, what content do you need to prep to make it all work?

Final Thoughts

This is just the first of at least two world building posts for aquatic settings, and was focused mainly on getting the framework set up. Aquatic settings are a lot of fun, but there’s a few extra moving parts to track, and I hope that this is making it easier. The next post will be diving hard into some cultural aspects of aquatic settings to consider. #AquaticSummer Continues!

Read the rest of the series here: [Part 1][Part 2][Part 4][Part 5][Part 6][Part 7][Part 8]

Exit mobile version