Which Lego game allows players to explore a fully open-world version of Lego City?

The Lego game that lets players explore a fully open-world version of Lego City is Lego City Undercover.

Released in 2013, Lego City Undercover follows Chase McCain, a police officer returning to Lego City to pursue escaped crime boss Rex Fury. Instead of restricting players to a sequence of disconnected stages, the game places those missions around a large explorable city hub filled with vehicles, collectibles, puzzles, buildings, and hidden areas.

Chase gains different disguises during the story, and each disguise provides abilities useful for solving puzzles or reaching previously inaccessible locations. Players can drive cars, boats, and helicopters, while Lego studs and bricks support vehicle purchases and larger “superbuild” constructions.

The game was notable because it was not based on a film or comic-book license. It was developed by TT Fusion around the original Lego City toy line and used a cheerful police-adventure setting rather than the darker tone associated with many open-world crime games. The original version launched as a Wii U exclusive, using the GamePad for maps, scanning, and other police tools. A 2017 release added versions for Switch, PlayStation 4, Windows, and Xbox One, plus local multiplayer.