Justin Bieber was arrested for DUI … TMZ has learned.

Law enforcement tells us … Bieber was busted in Miami Beach and it didn’t end with DUI … he was also busted for drag racing.

The arrest occurred early Thursday morning.

Bieber is now in custody and is at the police department where he is being tested — presumably to more precisely measure his blood alcohol level.  Our law enforcement sources say Justin was given a field sobriety test at the scene … and failed.

His next stop will be jail, where he will be booked and processed and bail will be set.

We’re told Bieber had just left a club and was driving a yellow Lamborghini at the time cops spotted him in a residential neighborhood.  Sources say the person Justin was racing was also arrested — he was in a red Lambo.

Justin had a passenger in the car — a model.

Based on what we know … the traffic stop was for drag racing and cops determined he was driving under the influence.