Reef.IO vs Tic Tac Toe

Most addictive game ever! Collect all of the fish in sight and school your enemies! Can you be the king of the reef?

Think you know Tic Tac Toe? Think again. Twelve game modes, three AI difficulty levels, and a Survival mode that will push you to the limit — all offline, no account required. GAME MODES • Classic — The original 3×3. First to line up three wins. • 5×5 — A bigger board where four in a row takes the game. More room, more traps. • Order & Chaos — One player tries to make five in a row, the other tries to stop it. Either side can place X or O. • Infinite — Only 3 pieces on the board at a time. Your oldest disappears when you place a 4th. Every move could be your undoing. • Numerical — Forget X and O. Place numbers and be the first to reach a sum of 15. Strategy has never felt so different. • Pick 15 — Claim cells from a shared pool of digits. First to own three that add up to 15 wins. • 3D — Three dimensions, three layers, 49 ways to win. The deepest Tic Tac Toe you have ever played. • Misère — Same board, opposite rules. Get three in a row and you lose. Force your opponent into the line to win. • Wild — Place either X or O on every turn. The first to complete any three in a row wins. • SOS — Spell "SOS" on a 5×5 grid. Every word you complete scores a point and earns another turn. Highest score wins. • Quixo — Pick, flip, and slide cubes to push five of your symbol into a line. A modern classic. • Ultimate — A 3×3 grid of 3×3 boards. Your move decides where your opponent must play next. Think several steps ahead or fall behind. SURVIVAL MODE Win as many rounds as you can — but one loss ends everything. Each round throws a different game mode at you. Beat it for 2 points. Draw for 1. Lose and it's over. Your best score is saved. Can you beat it? CHALLENGE THE AI Three difficulty levels built for every skill level: • Easy — Relaxed and forgiving. Great for beginners. • Medium — Tactical and competitive. Will make you think. • Hard — Minimax algorithm with alpha-beta pruning. It learns from its losses. Good luck. PLAY WITH FRIENDS Pass and play locally with anyone. No Wi-Fi, no accounts, no limits. CLEAN & THOUGHTFUL DESIGN • Light and dark theme • Satisfying sound effects and haptic feedback • Fast, smooth gameplay • Available in 30+ languages