How to Play Coralbay: Complete Rules Guide | Playgridia

2026-08-10

Coralbay is a free browser engine builder for 2–4 players, played across three depth bands of a coral reef. It is the calmest game on Playgridia and one of the most demanding, for the same reason: there is no attacking, no blocking and no elimination. Nobody can touch your cove. Every point you score, you built — and every point you missed, you had the turns for and spent somewhere else.

This guide covers a whole match from an empty cove: setup, every action, how the chain works, where points come from and what the room options change. If you have never opened the game, it is enough to sit down and play.

The board: three bands, four slots each

Your cove is a mat of three rows and depth increases downward: the shallows on top, the reef in the middle, deep water at the bottom. Each row has four slots, so a cove holds twelve creatures — comfortably more than one match will ever fill, which is deliberate.

Each band is two things at once: somewhere creatures live, and an action you can take. The shallows gather food, the reef places pearls, the deep draws cards. The table shares a tide pool of six food dice, three face-up creature cards beside the deck, and the three goals of the match.

Setup: keep four things, pick one chart

You are offered four creature cards and four foods — one plankton, one kelp, one krill, one squid — and keep four things in total, in any mix. Four cards and no food is legal; so is one card and three foods. Keeping cards you cannot afford to feed is the classic first-game mistake, so if you are unsure, lean toward food.

You are then shown two secret charts and keep one. Only that chart scores, at the very end, and it is worth roughly 5 to 11 points to somebody who builds toward it — enough to tilt a match, never to decide one. Charts reward filling a single band, collecting one home type (coral, sandbed or grotto), hoarding pearls, stocking your larder or building big shoals.

Finally three shared goals are dealt, one per tide, and all three are face up from turn one. Apart from each player's own chart, nothing here is hidden.

The turn: one action, and that is the whole design

On your turn you do exactly one of four things:

• Gather food (shallows) — take food dice out of the tide pool.
• Place pearls (reef) — put pearls onto creatures you have already settled.
• Draw cards (deep) — take creature cards from the face-up tray or the deck.
• Settle a creature — pay its food cost and the column's pearl cost; it takes the leftmost free slot of a band that accepts it.

What a band pays depends on how many creatures already live there. The shallows run 2 food → 2 food and a card → 3 food → 4 food. The reef runs 2 pearls → 3 → 3 pearls and a food → 4. The deep runs 1 card → 2 → 2 cards and a pearl → 3. So every creature you settle upgrades its row immediately, before it has done anything else.

The chain: left to right, and the Current

Here is the mechanic the game is built on. Take a band's action and every creature in that row activates, left to right. The one you settled first fires first, and because slots fill from the left, the order you build in is fixed for the rest of the match. By the third tide a single tap can wake five or six creatures in sequence: each creature raises the row's base reward and lengthens the phrase that fires every time you use it. Cash in today, or make the chain longer.

Fill a row's last slot and the chain does not stop at the edge. The Current carries it one step further: the first creature of the next band down answers with one more activation, wrapping from the deep back round to the shallows. One extra trigger, never more — the only place in the game where a single action reaches two bands, and the payoff for committing to one row instead of spreading across three.

What settling costs, and where food comes from

A creature costs the food printed on its card plus a pearl toll for its column: the first two slots are free, the third costs 1 pearl and the fourth costs 2. The two cheap slots are also the two that fire first — your opening is free, and permanent.

Food comes out of the tide pool: six dice showing the four foods plus a wild face, and one face in five is wild, taken as any food you name. The pool tops back up at the end of every turn instead of draining and resetting, so it is full when your turn comes round and sitting last never means a picked-over tray.

One warning for turn one: on an empty cove the reef action is wasted, because no creature can hold a pearl and the reward vanishes. Start in the shallows.

The four power colours

Every creature carries one power, and its colour tells you when it happens:

• Brown — when triggered. It fires when you take that band's action. This is the chain.
• Teal — when it settles. A one-off, the moment the creature arrives.
• Yellow — end of tide. It pays at the end of every tide. Settle one in the first tide and it pays three times.
• Pink — on a rival's turn. Food, a card or a pearl arriving while somebody else plays.

One power is worth naming on its own: the hunt flips the top card of the deck, and if the creature swimming past is shorter than your hunter's reach it joins that creature's shoal and is worth 1 point. No power ever stops the game to ask a yes-or-no question. When one needs a real decision the bottom bar opens and you pick a die, a creature or a card — and a choice with only one legal answer resolves itself.

Three tides, and how the match ends

A match is three tides of 9, 7 and 6 turns — twenty-two turns each, with the counter always on screen. At the end of each tide, that tide's shared goal is scored by ranking against the table rather than a fixed threshold: at two seats 6 and 2, at three seats 7, 4 and 2, at four seats 7, 5, 3 and 1. A seat measuring zero never scores, but with three or more players even last place in the race is paid.

When the last turn is played, everything is counted: creature points (0–9 on each card) + 1 per pearl + 1 per stored food + 1 per card in a shoal + your three goal results + your secret chart. Ties break on the food and cards left in hand. A typical four-player match finishes near 70 points with about half the twelve slots filled — an unfinished cove is normal, and deliberately so.

Room options, and a plan for your first match

Two options in the room. Pace is classic (9/7/6) or swift (7/5/4). Season is the light on the water — turquoise lagoon, sunset or moonlit — changing the palette, the backdrop and the music the game composes for itself, but not a single rule.

For a first game: spend early turns in the shallows, because food pays for everything. Do not scout a hand you cannot afford to settle. Get a yellow power down in the first tide, while it still has three payouts left. Aim two or three creatures at whichever goal you can actually reach, since ranking pays even when you lose the race. And on a rival's turn the board shows their cove and names each step at the bottom of the screen — watch how somebody else's chain was built, then tap your own chip on the top rail to come home.

That is the whole game. Play Coralbay free in your browser — open a room, add an Easy, Medium or Hard bot or invite a friend, and your first creature is thirty seconds away. No download, no account.

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