At the end of November 2015, a final design proposal for the successor of the F30 3 Series by Alexey Kezha out of 3 total, was chosen by BMW management, as reported by Auto Bild in October 2015.

[12] The G20 3 Series is based on the Cluster Architecture (CLAR) platform and features increased use of high-strength steel and aluminium.

The long-wheelbase variant (G28) in China was launched in April 2019 as a single trim, the 325Li, which uses the same 2.0 liter turbocharged engine making 184 hp and 300 N⋅m (221 lb⋅ft) of torque as the global 320i and is mated to a 8-speed automatic transmission as the only drivetrain offered.

[29] This version was subsequently released in selected Southeast Asian markets like Thailand and Malaysia, complementing the existing standard-wheelbase variants already sold there.

[34] Standard equipment includes full LED headlights and tail-lights, automatic climate control, automatic headlights and rain-sensing wipers, 40:20:40 split folding rear seats, and driver assistance systems including lane departure warning and collision warning with braking intervention.

[36] The system could be upgraded to iDrive 7.0 with a 10.25-inch display and 12.3-inch digital instrument cluster called "Live Cockpit Professional" with plug-in hybrid models receiving it as standard equipment.

[37] iDrive 7.0 has over-the-air updates for the navigational maps and operating system, and features a voice-controlled digital assistant that can be activated by saying "Hey BMW".

[40] A Digital Key system enables a smartphone to lock or unlock the vehicle using near-field communication, and will start the engine when placed in the wireless charging tray.

This includes a splitter, lip spoiler, tailpipes, sport brakes, darker taillights and more carbon fibre parts.

The headlights have a new "inverted L shape" DRL signature (that is now standard on all models) and the top Laserlight option is replaced by new adaptive LED units with matrix high beam functionality.

Both feature new side air curtains, while the latter has a larger central intake (although part of it serves for design purposes only) and more aggressive styling.

The base version features body coloured graphics, while the M Sport has a large, gloss-black element that incorporates a faux diffuser and two vertically arranged reflectors.

The interior gets a significant update, with the dashboard being shaped by a new dual curved display that comes as standard and features iDrive with BMW Operating System 8.

[34] The BMW i3 sedan (model code G28 BEV) is a battery electric version of the long-wheelbase 3 Series (G28), and reused the nameplate from the i3 hatchback.

[59] The i3 eDrive35L introduced at launch is powered by a single rear electric motor offering 210 kW (282 hp) and 400 N⋅m (295 lb⋅ft), and a 0–100 km/h (0–62 mph) time of 6.2 seconds.

It features the same rear electric motor as the BMW i4 eDrive40 that reaches 250 kW (335 hp) and 430 N⋅m (317 lb⋅ft), a 0–100 km/h (0–62 mph) time of 5.6 seconds, and a range of 592 km (368 mi) (CLTC).

The handling is also reworked with a wider track, high performance tyres, stiffer springs, adaptive dampers, larger-diameter disc brakes and four-piston calipers.