Tic tac toe apps differ in who you can play (the computer, someone on the same device, or opponents online) and in whether they keep the classic rules or change them. Classic 3x3 tic tac toe between two careful players ends in a draw, which is why some apps add pieces that disappear. Each blurb below is drawn from the app's own App Store description.
Tic Tac Toe ∙
Classic tic tac toe with one and two player modes, a computer opponent at three difficulty levels, and turn-based network play of up to 16 games at once against Game Center friends or random opponents. It has score tracking and undo, and it is supported by banner ads. App Store
Mega Tic Tac Toe Online
Classic tic tac toe with online play against other players, a computer engine to play against, a two player mode on one device, and live rankings and leaderboards. App Store
Tic Tac Toe OXO - 2 Player
Classic 3x3 tic tac toe against the computer at several difficulty levels or pass and play with two people, with three themes (Modern, Chalk, Neon Glow) and 35 avatars to choose from. App Store
Infinite Tic Tac Toe Game
A disappearing-piece variant: after six moves on the board, the oldest piece disappears every turn. It offers single player against the computer at three levels, pass and play, online play through Game Center, an Apple Watch version and a one-time Shield that protects a piece. App Store
Ours
Jolt: Tic Tac Toe
Each player keeps three pieces and no board position may repeat, so every game ends with three in a row. Play the computer at three levels, pass one device between two players, or create an online room with a six-character code (creating a room needs Jolt Pro). About it · App Store
Questions people ask
Why does tic tac toe always end in a draw?
Classic 3x3 tic tac toe is a solved game: if neither player makes a mistake, it ends in a draw. Variants change the rules, for example with pieces that disappear, so the board keeps moving and a tie stops being the default.
Can I play tic tac toe with a friend on another phone?
Yes. Several apps offer online play, some through Game Center invites or matchmaking, and Jolt through a room code you send to a friend.