Nurikabe is a Japanese grid logic puzzle: mark each cell as island (land) or sea (shaded) so every numbered clue becomes an island of exactly that many connected cells, no two islands touch, and every shaded cell forms one single connected sea with no 2x2 block of shading anywhere. Tap a cell to cycle blank, sea, and land, then check your work against the numbers. Free to play online with no download, no sign-up, and no timer pressure — 10 levels grow the grid from a quick 6x6 warm-up to a full 10x10 challenge, and works on both touch and desktop.
How to play Nurikabe
- Start on a grid where some cells already show a number — each numbered cell is the seed of an island, and the number is exactly how many connected cells that island must total.
- Tap any other cell to cycle it through blank, sea (shaded), and land (part of an island), building up which cells belong to which island and which are open water.
- Every island must be one orthogonally-connected group of land cells containing exactly one number, and no two different islands can touch — not even diagonally counts as safe if their cells share an edge.
- Every cell that is not part of an island is sea, and all of the sea must connect into a single shape with no 2x2 block of four shaded cells anywhere — mark every cell correctly and the level clears automatically.
Tips
- A blank cell squeezed between two different numbered islands (or an island and the grid edge, with no room to grow the island past it) is always sea — mark it first to shrink the puzzle.
- Count outward from each clue: an island of size 3 can only reach 2 cells away from its number in any direction, so any cell further than that from every clue must be sea.
- Watch for 2x2 blocks while you shade sea cells — if marking a cell would complete an all-sea square, that cell has to be land instead, even if you have not worked out which island it belongs to yet.
- If two clues are only one or two cells apart, work out both islands together — the cell between them usually can only belong to one of the two without letting them touch.
FAQ
Is Nurikabe free to play?
Yes. Nurikabe is completely free to play online with no download, no account, and no in-game purchases.
Does Nurikabe work on mobile?
Yes, it works on touch devices as well as desktop with mouse and keyboard — tap or click a cell to cycle its mark.
What do the numbers in Nurikabe mean?
Each number is the total size of the island it belongs to, counting the numbered cell itself. An island is a group of connected land cells with exactly one number in it — so a "4" means that island covers 4 cells total, whichever shape they end up forming.
How many levels does Nurikabe have?
There are 10 levels, ramping the grid from a 6x6 warm-up with 4 islands up to a full 10x10 grid with 9 islands. Progress and your best unlocked level are saved automatically in your browser.