Sea Diamonds Challenge is a tile-matching game with an underwater setting. The player attempts to complete a task during levels play or earn the highest score possible during timed play. Unlike many tile-matching games, they don't need to create match-3 rows or columns. Instead, they select three or more pre-existing identical diamond tiles that share at least one side. The game is similar to Halloween Monster Puzzles, Melodic Tiles, and Tiles of the Simpsons.
The player starts by selecting either a skull-and-crossbones icon for levels play or a fiery stopwatch icon for timed play. A timer counts down with both options. With levels play, the player must reach a specific points level before they run out of time to unlock the next level. With timed play, they merely need to earn as many points as possible before no more time remains.
If the player removes sets of three or more identical tiles without disruption up to nine times, they receive a powerup ability that blasts away non-matching tiles in a large area for a few seconds. If they accidentally touch one or two diamond tiles, they lose their continuous play status or the powerup.
Seas Diamonds Challenge makes the player start over when the game ends, which means they're bumped back to the first level or zero points, depending on the mode. That said, if the player runs out of moves before time runs out, they need to watch the 10x10 board carefully. The game automatically transforms a single diamond tile into a different type and color randomly, which can open up match opportunities.
