Sea Battle: Rules and How to Play
Sea Battle is a 15-minute game for 2: hide your fleet on a 10×10 grid and take turns firing at squares to sink your opponent's ships. Sink them all first to win. Free in your browser, no sign-up.
Setup
- 2 players. On your own, play against the computer.
- Your waters are a 10×10 grid (rows A–J, columns 1–10). Place a carrier (5 squares), battleship (4), cruiser (3), submarine (3) and destroyer (2).
- Ships go straight across or down — never diagonally, and never overlapping. Ships may touch.
- Your fleet starts laid out for you. Tap a ship, then tap a square to move it; Rotate turns it and Shuffle lays the fleet out again. Tap Ready when you are done.
How to play
- Starting with the first player, take turns firing at one square in enemy waters.
- If a ship is there it is a hit, and you are told which ship. Otherwise it is a miss.
- When every square of a ship has been hit, that ship is sunk.
- Use your hits to work out which way a ship runs, and narrow down where the others can hide.
Winning and scoring
- The first to sink the whole enemy fleet wins.
Defaults on this site
| Item | Default on this site |
|---|---|
| Players | 2 players (set automatically by the party size) |
| Turn time limit | None by default (the host can set 30 or 60 seconds) |
| If someone drops mid-game | Reopening on the same device returns you to your seat. If you do not return, the CPU plays in your place. |
| Draws | In ranked play, a draw counts as halfway between a win and a loss for your rating. |
| Source of the rules | Based on the standard reference rules |
Rules supervised by Qdan, Inc. (based on the standard reference rules)
House rules
Defaults follow the standard reference rules. The party can change these.
| Name | Description | Default | Changeable |
|---|---|---|---|
| Fleet | Five ships (carrier, battleship, cruiser, submarine, destroyer) or ten ships (one of 4 squares, two of 3, three of 2, four of 1). | Five ships | Can be changed |
| SalvoSalvoA salvo is a volley of shots. Each turn you fire one shot for each of your ships still afloat, so losing ships means firing fewer shots. Whoever sinks ships first pulls further ahead, and games finish faster than one shot at a time. | Each turn, fire one shot for every ship you have left (five at the start). Pick the squares, then tap Fire. | Off (one shot a turn) | Can be changed |
| Fire again after a hit | After a hit you fire again, until you miss. Not used with Salvo. | Off | Can be changed |
| Ships may not touch | Ships cannot be placed next to each other, corners included. | Off (ships may touch) | Can be changed |
| Keep hit ships secret | A hit does not say which ship was hit; you only learn a ship's name when you sink it. | Off (every hit names the ship) | Can be changed |
| Swap first player on rematch | Play again switches who fires first. | On | Can be changed |
Terms
- Hit
- A shot that lands on a ship. You are told which ship (a local rule can keep this hidden).
- Miss
- A shot that lands on open water.
- Sunk
- A ship whose every square has been hit.
- Salvo
- A way to play where you fire one shot per ship you have left, all at once.
FAQ
Can ships go diagonally?
No. Ships go straight across or down.
Can ships touch?
Yes, by default. The local rule “Ships may not touch” forbids it.
What is a salvo?
A way to play where you fire one shot per ship you have left each turn. The more of your ships are sunk, the fewer shots you get.
Play now with these rules
Last updated 2026-09-19 · Run by Qdan, Inc.