Underwater Cities is most commonly compared to Terraforming Mars – fairly, i think. Both board games have you cozying up an inhospitable environment by playing cards to a tableau to build an ever-powerful engine. But unqiue mechanic here – matching a card colour to a worker placement space – makes Underwater Cities unique enough in its own right.

(click to view transcript)

Hi! It’s Ryan from Nights Around a Table, and this is Underwater Cities, a route- and engine-building worker placement game for 1-4 players. Let me show you how to play!

Planet earth topside is pooched, so you and your friends are leading the expansion of humankind into the almost-final frontier by building … Underwater Cities. Underwater Cities.

You’ll simultaneously claim action spaces and play cards – 3 each per round – in order to build two different types of domed cities, the 3 different types of buildings that support them, and the 2 different types of tunnels to connect them, all while building an ever-powerful engine that you’ll get to run 3 times during the game. At the end of three production cycles, everything you’ve built gets you points, and whoever has the most points, wins!

Here’s the main game loop: each one of these ticks is a round. Each round, each player takes turns taking three different actions on the common board, and playing a card alongside each of those actions – and if the colour of the card matches the colour of the action, you get to build the card to your tableau, too! The actions and the cards let you build a bunch of stuff, and when you reach this first production phase, all the stuff you’ve built pays you a pile of money and resources and points. Then you repeat this process, taking actions and playing cards and building stuff until it all pays out again in the second production phase, and then one more batch of three rounds gets you to the third and final production phase where you get more money and resources and points. Then the stuff you’ve built gets you even more points, and you cash in all your leftover resources for money and money for points to see who’s won the game.


So the unique mechanic going on here is that there are three groups of worker placement spots – green, red, and yellow. The green spaces are kind of sucky, the red ones are decent, and the yellow ones are really powerful. On your turn, you’ll place one of your three workers – what is that? Some kind of door? – on one of these spots, where you get to do the thing.

But at the same time, you’ll play one of the three cards from your hand. The cards are also green, red, and yellow, but their power levels are reversed: green cards are the best, red cards are okay, and yellow cards are the suckiest. If the colour of the action you select and the card you play match, you get to claim the card and put it out in front of you. Par for the course with worker placement games, once you put your… access card? Metal belly button? ….on an action space, nobody else can place there.

Then, there are a few rules about what you get to do and in what order. Certain action spaces let you do multiple things. You can do those things in any order. So here, you can build a tunnel first and then a city, or the other way around. Or, you can just build a tunnel, or just build a city. But you have to be able to do at least one of these things, or you can’t place your… Buck Rogers belt buckle there. Spaces with a slash mean “or” – you can do this OR that, but not both things.

If the colour of the card you play when you take the action space matches, you get to put the card in front of you. If it doesn’t match, you have to discard the card. If the card has a lightning bolt on it, that means you get to do this stuff right away. If the card lets you do multiple things, you can do all or some or none of those things. And you can do the card stuff either before you do the action space stuff, or after you do the action space stuff. The only thing you can’t do is interweave actions between cards and spaces – so you couldn’t do 1 thing on a card, and then 1 thing on the space, and then another thing from the card, and another thing from the space. It’s card and then space, or space and then card.


There are 4 resources in the game: kelp, steelplast, science, and money, along with a fifth, more valuable resource called biomatter. You’ll use those resources to build cities – either white ones or purple ones, which look more red than purple if you want my honest opinion – tunnels to connect the cities, and three different kinds of buildings: green farms, yellow desalination plants, and white labs.

You get a little card that shows you what each construction costs: each of the three buildings costs the resource that matches its colour. Tunnels cost a steelplast and a credit. White cities cost 2 steel, a kelp and a credit, while the more expensive purple symbiotic cities don’t need that second steelplast, but you need to pay a biomatter token in its place. And biomatter’s not easy to come by. Biomatter can act like a wild resource when you’re building something – it can stand in for a steelplast or a kelp. But it can’t stand in for a credit or a science token.

But this next column shows you what you’ll get from each thing when the production phase happens at the end of the era: farms get you kelp, tunnels and desalination plants get you money, labs get you science, white cities get you nothing, and symbiotic cities get you 2 points. Cool.

By taking certain actions or playing certain cards, you can also upgrade your tunnels and buildings to make them more valuable. An upgraded farm gets you an extra point during production. An upgraded desalination plant gets you an extra biomatter, and an upgraded lab gets you a steelplast on top of the science it already produces. An upgraded tunnel gets you an extra point. Biomatter can only stand in for a kelp or a steelplast when you’re building – it can’t stand in for a science token when you’re upgrading.

And finally, the game rewards you for having a pair of upgraded buildings servicing the same city. Two boosted farms next to the same city will pay out an extra kelp and an extra point. Two jacked-up desalination plants at the same city will get you an extra credit, and two supremo labs in the same city will get you an extra steelplast.

After you get all the goodies from the stuff you’ve built during the production phase, you have to pay 1 kelp per city you’ve built to keep your people fed. If you can’t pay a kelp, you can pay a biomatter, but… ouch. And if you don’t have kelp or biomatter, then for every city you aren’t able to feed, you lose 3 points. You can’t go below zero points.

There are a few rules governing where and how you can expand your… Underwater Cities. You start with one city at the bottom right of your board. Any new city you build has to be adjacent to an existing city – and adjacency means both diagonal and orthogonal. So your second city can go here, here, or here. If you build the central city, all of the spots on the board are available to build a city, since that central site is adjacent to all of them.

Interestingly, you don’t actually have to have any tunnels connecting the cities you build, but cities that aren’t connected by tunnels won’t pay out during the production phase.

As for tunnels, you can build them anywhere on your board, as long as you can trace a path back to your starting city. So you can build one here and then here (2 to the left), or here and then here and then here (middle, top right, then down), but you couldn’t just plop one out here in the middle of nowhere. Tunnels that aren’t adjacent to cities don’t pay out during the production phase – so this one gets you a credit, but this one gets you nothing.

Buildings can go in the spaces around any city, or in the spaces around any spot where you could build a city. So since you could build a city here, you can put a farm on this spot. But since you couldn’t build a city here, since it’s not adjacent to any existing city in your network, you likewise couldn’t build a farm – or any other building – on that site. During production, any building that isn’t surrounding a connected city doesn’t pay out.

All city sites have three possible slots for buildings. Each site has a fourth expansion slot that’s locked – you can’t build anything there unless you play a card that says you can.

If you build cities or tunnels on top of spots that have prizes printed on them, you get to claim those prizes.

Everyone also has these randomly-dealt coastal metropolis tiles on their boards. The two blue ones get you some sort of perk if you’re able to tunnel out to them.The brown one has some big end-game bonus you can claim, but you have to build two tunnels in the last leg to reach it. This brown metropolis often helps guide your strategy from the beginning of the game – i start here, and i need to build up to here, and i need to build in such a way that i get the most possible points from that tile. If you’ve tunnelled out to a metropolis that activates during the production phase, it’ll activate, but the metropolis doesn’t count as a city, so in this situation, this tunnel would produce a credit for you, but this one wouldn’t, even though it’s touching a metropolis.


The Rules Gremlin wants me to go back to the cards to explain a few rule nuances.

For startsies, your hand limit is 3 cards. Whenever you select an action with your…tacky cigarette holder.. You play a card. Do the thing, and the thing on the card if the colour matches – in whatever order serves you best… and then end your turn by drawing a card to bring you back up to your limit of 3. Because some actions and cards let you draw more cards, you may end up with more than 3 cards at the end of your turn. You need to whittle your hand down to 3 cards by the time play comes back around to you, before you take your next turn. You may discover abilities later in the game that let you hold on to more than 3 cards.

Not all cards are created equal – they have different symbols at their top left corners, indicating that they behave in different ways. The lightning bolt cards fire off immediately, if you play them and they match the colour of the action space you chose. If you match the colour of a permanent effects card, it goes out in front of you and gives you some sort of perk or power for the rest of the game. A colour-matched production card goes out in front of you and fires off whenever a production round happens. Colour match a card with a stopwatch, and it goes out in front of you until the end of the game, where it may get you some end-game bonus points. And finally, if you match the colour of your chosen action space to the colour of an Action card with a letter A on it, you get to claim that card and put it out in front of you. But you don’t actually get to do what’s on that card. Yeah – the Rules Gremlin makes a good point: we found these Action cards to be the most confusing part of the game, so pay attention:

If you match the action card colour to the space, you get to claim the action card and put it in your tableau. Everyone starts the game with an assistant action card already claimed and sitting out in front of them. The artwork is different on all of these assistants, but they all do the same thing. The dolphin and the doctor are also low-key insulting, but that’s okay, because you can get rid of them, which i’ll explain in a sec.

If you take an action space with this capital letter A on it, you get to pick one of the action cards you have out in front of you and use its action. You turn the card 90 degrees to remember you’ve used it, and action cards don’t refresh until the next era, after the production phase. So it can get a little confusing if you take an action and play a matching action card on the same turn: because the card matches, you get to claim it by putting it out in front of you. And because the action has an A on it, you get to use one of your available action cards – which could be the action card you just claimed in this turn. But it doesn’t have to be. Could be this one.

The temptation is to take a space and play a matching action card and do the action on the card. But no – if the space doesn’t have an A on it, you don’t get to do what’s on a matching Action card you play – you only get to claim the matching Action card by putting it out in front of you. But Ryan, you say – i thought you told me that if you take an action and the colour of the card you play matches that action’s colour, you get to do the thing on the card? Well, yes – but in the case of Action cards with the little A on them, the thing you get to do if the colour matches is to claim the card by putting it in your tableau.

The highest number of action cards you can have out in front of you is 4. If you claim a fifth, you have to get rid of one you’ve already claimed. But the good news is that when you do that, if the Action card you’re getting rid of is untapped, you get to fire off that card’s ability in one final hurrah!

Dolphin: Don’t discard me! Everyone loves dolphins!

Take a hike, you sanctimonious sex pest.


If you claim an action space with your… Trump Tower elevator button … that has a big S on it… that lets you take one of the special cards in the middle of the board. The six cards here usually have end-game bonuses on them, and they’ll cost you 3 credits to play out of your hand on a later turn. These six cards are limvvited – once they’re gone, they’re gone.

The cards in this deck cost 1 or 2 credits to play. If you want one of these, you can either take the top 1 as-is, or bury the top one, turn up 3 more, take one, and bury the other two. Once you’re done messing around with this deck, turn up the top card again.

Special cards work like any other card, except for the money they cost to play. If you play them while taking an action space that doesn’t match the colour of the card, you have to discard them without paying and without getting their benefit. If the card matches but you can’t or don’t want to pay for it, you can discard it. Discarded 1- and 2-credit Special cards go back to the bottom of their deck,c unless they have instant effect lightning bolts on them – if you use or discard one of these, just tuck it under your board. It’s a rare situation that you’d get rid of a 3-credit Special card, but if you do, just return it to the box.


Most of the symbology on the action spaces is self-explanatory, but a couple of spaces need explaining.

This symbol moves your marker up 1 on the Federation track. If you reach these spaces, you get the prize indicated. If you’re already at the top and you get to move up again, you get 1 point for every space up you were supposed to move. If you move up the track and other players are in the way, your token stacks on top of theirs. At the end of the round, the position of the markers on the Federation track determines turn order, as we’ll see shortly.

This space lets you either take 2 science tokens, or pay science tokens to upgrade up to 3 of your tunnels or buildings – 1 science token per upgrade.

This space lets you fire off one of your claimed Action cards, and/or buy a building or tunnel at the usual cost, and then pay 1 science to upgrade it. Unlike the other action spaces, this action can’t be split up: if you build a thing, you must then pay 1 science to upgrade it. You can’t just build the thing and not pay the science.

In the middle of the board is this Always-Available space. Since it’s blue, it never matches the card you play, so wh enever you go there, you’ll just have to discard a card. Multiple players can choose this slot. It gets you 2 cars and 2 credits. Some Special cards tell you you can use the benefits of other action slots – those cards don’t work with the Always-Available space.

In 4-player games, there’s this action-cloning tile. If you pay a credit, you can claim it, and put your … golden ding-dong … on an action space that’s already occupied by another player, and then play a card and do the thing as usual. You can’t use the action-cloning tile to claim a space you’re already on – it has to be one claimed by another player. The action-cloning tile can only be claimed once per round.


Once everyone has placed their 3 … El Dorado doorbells … and played their 3 cards, the round is over. Take back your action tiles, and return the action-cloning tile in a 4-player game if someone claimed it. Next, you have to reorder the turn order track according to where the markers are on the Federation track – just match what’s there from the top down. Tokens that are on top of other tokens have higher priority. If two or more tokens are down here in the pits, they maintain the same order they had last round.

Advance the round marker 1 step. If this puts you in a production phase, then all the stuff you’ve built will pay out. All your Action cards refresh… and you bust out a new deck of cards for the next era of the game. Everyone gets 3 more cards in addition to the cards they’re already holding and, as usual, you have to discard down to 3 cards before you begin your next turn.

If this is the end of the game, you perform the third and final production phase before counting up your endgame points.


After the third and final production phase, refer to this handy player guide to count up the rest of your points.

First, if you’ve double-tunnelled out to your brown metropolis, count up any points it gives you. Then, count up the points on any card you’ve played with a stopwatch on it.

Every tunnel and city pair gets you 2 points. If the city has at least one building next to it, it earns you 3 points. If there are two different colours of buildings there, the city is worth 4 points, and a city and tunnel pair with all three types of buildings around it gets you 6 points.

Then, boil down all your leftover resources for money – i credit per tile. Biomatter gets you 2 credits. And once it’s all converted to money, every 4 credits buys you a point.

Whoever has the most points wins, and turn order breaks ties.


To set up the game, put the main board in the middle of the table, on the 1-2 player side or the 3-4 player side depending on your player count. Shuffle and deal out six Special 3-credit cards to this section of the board. Shuffle the 1- and 2-credit Special cards and place them here, and then turn over the top card. In a 4-player game, put the action-cloning tile here.

Everyone picks a colour and gets a player board, a one-as these, one-a these, and the insulting assistant in his or her matching colour. Take the three… pieces of 10th grade musical costume jewelry… in your colour. You start with 1 city at the bottom right of your board, and a randomly-dealt brown metropolis here, and two random blue ones here and here. Everyone gets a kelp, a steelplast, a science, and 2 credits to start the game.

The boards are double-sided. The flip side has these red-outline surcharge areas where you have to pay extra to build there, but it also has these double- and triple-payout icons that amp up the production benefits of certain structures.

Put a token for everyone on zero. Shake up another set of tokens and place them on the play order track. Then take the last set of tokens and put them in reverse order on the Federation track – so the top guy here goes on the bottom, and then on up. Whoever winds up here gets an extra credit to start the game, and this player gets 1 extra credit and 1 extra steelplast to start.

Most of the resources in the game are unlimited, but some aren’t. The white city domes are limited to 17 per game. The purple symbiotic city domes are limited to 7, 10, and 13 in a 2, 3, and 4-player game. The tunnels are limited too – once they’re gone, they’re gone. The 3-credit Special cards are limited to whichever 6 cards you deal out off the top of the game.

If you’ve opted to play with these government contract cards, deal 3 of them at random to the main board. If you meet the requirements of one of these cards during your turn, you claim the card and get the benefit. The contract cards don’t get refreshed.

Later printings of the game include this biodome promo. If you’re the first player to have 3 connected cities, you get to replace your starting city with this one-of-a-kind green dome. The green dome is nonsymbiotic, like the white ones, so it doesn’t earn you any points during production. But it’s also self-sustaining, so you don’t have to feed it any kelp during production.


To play solo, use the 2-player side of the common board… and the advanced side of one of the player boards. Don’t play with the government contracts. Set up the game for 2 players, but if you deal this brown metropolis, get rid of it and deal something else.

Block off the rightmost action going clockwise using another player colour’s… C3PO’s nipple clamps. Your token starts at the bottom of the Federation track. Since you always go first, you don’t need to put another token on the other half of the track.

When a round ends, rotate the action tiles to block the next spot in order. If you’re still at the bottom of the Federation track, you suffer the penalty of another blocked slot. Draw a card from the era deck, add its digits together – so here, it’d be 2 + 6, so 8… and starting with this green action space, count 8 spaces clockwise – 1 2 3 4 5 6 7 8. If the space you land on is empty, add another non-player tile to block the space. If it’s already occupied, move the tile clockwise until it hits an empty space to block.

To win the solo game, you have to finish with at least 7 connected cities and at least 100 points. On every successive solo play, try to beat your high score.

And now, you’re ready to play… Underwater Cities.

Get Your Own Copy of Underwater Cities

i’m happy to report that Underwater Cities plays well at 2 players! My wife Cheryl and i both enjoyed it. You may remember that this (and the expansion Underwater Cities: New Discoveries) was the game i chose to buy for my birthday last year. i wasn’t disappointed! It was nice to nestle everything into a wooden LaserOx insert.

To add your own copy of the game to your board game collection, use the Amazon link below. Your price will remain the same, and i’ll receive a small commission.