The Mazda3 Mk1 (code: BK series) marked Mazda's bold entry into the compact car segment, replacing the long-running 323/Protegé. It debuted in 2003 and remained in production until 2009. Available as both a 4-door sedan and a 5-door hatchback, it was built on Ford's global C1 platform, shared with the Ford Focus and Volvo S40. A facelift arrived in 2006.

Models had manual or automatic air conditioning panels. Optional Bose premium sound systems and some models had the Mazda SDAL navigation screen.