Crossword Island is a word puzzle game that shares similarities with classic crossword puzzles. It has a sailing and island theme and construction mechanics as well. The game has at least six modes and new island challenge levels (Island 1, Island 2, Island 3...). Each level requires that the player win a higher number of crossword-style puzzles than the last one.
The player travels via a wooden ship with a red-and-white striped sail to different areas of the sea to construct islands. They must complete crossword puzzles successfully to fill a new area of an island with architectural wonders and decorative elements. Each crossword features empty character space tiles arranged in horizontal rows.
Unlike classic crossword puzzles, solved letters don't help the player determine the answers to column questions. In fact, the early levels don't even have columns to solve.
Crossword Island acts a bit like the Wheel of Fortune game show. When the player answers a clue with the correct word, the game places some of the new letters in empty spaces on other rows.
The game also offers help similar to match-and-merge games. The player can use coins to buy a letter, a few letters or an entire word. If they run out of money, they can earn more by watching advertisements.
The player can also explore past completed islands or levels and see the outlines of future ones in their sailing ship.