The Union Cabinet approved Phase 3 in August 2024 at an estimated cost of ₹15,611 crore. It comprises two elevated corridors: JP Nagar 4th Phase–Kempapura (32.15 km) along Outer Ring Road West, and Hosahalli–Kadabagere (12.50 km) along Magadi Road. The expansion will take Bengaluru’s active metro network to 220.20 km.

BMRCL expects construction to start in June 2026 and operations in May 2031. Around 1,100 trees are approved for relocation on the JP Nagar–Mysuru Road stretch; planning reduced the overall tree count from over 11,000 to about 6,700.

The project includes 10 multimodal hubs, bus bays, station parking, footbridge links to Lottegollahalli and Hebbal railway stations, and cycle-sharing. Projected daily ridership is 4.63 lakh on Corridor 1 and 1.75 lakh on Corridor 2.

BMRCL is reconsidering a proposed 37 km double-decker flyover, potentially scaling it down to 11 km at congestion points including Hebbal, BEL Circle, Goraguntepalya, Sumanahalli, Nagarbhavi, Nayandahalli, Kamakya Junction and Sarakki Junction.

Indicative property prices: Nagarbhavi–Sumanahalli, about ₹7,000/sq ft; Magadi Road–Kadabagere, ₹9,900–₹16,550/sq ft; Peenya–BEL–Hebbal, ₹8,000–₹18,400/sq ft; JP Nagar and southern Bengaluru apartments, ₹8,550–₹16,300/sq ft.

Namma Metro Phase III comprises the 45km Kempapura–JP Nagar corridor on the Outer Ring Road and Hosahalli–Kadabagere corridor on Magadi Road. The Union government approved it in August 2024; Prime Minister Narendra Modi laid its foundation stone in August 2025, but work has yet to begin.

BMRCL proposed a 37km double-decker structure along the Orange Line, with a road flyover below the Metro viaduct, estimated to cost ₹9,700 crore, to be funded by the state. Following RITES’ advice, BMRCL is considering reducing it to around 11km of shorter stretches at traffic bottlenecks and will discuss the proposal with the state government. RITES cited risks of encouraging private vehicle use and engineering and operational challenges; structures could reach 35 metres. The Metro-only project’s EIRR is about 17%, compared with below the 14% benchmark with the double-decker component.

Potential bottlenecks include Hebbal, BEL Circle, Goraguntepalya, Sumanahalli Cross, Nagarbhavi, Nayandahalli, Kamakya Junction, Sarakki Junction, the Delmia flyover stretch and Vega City Mall. BDA has proposed a six-lane tunnel from Kanteerava Studio to BEL Circle via Goraguntepalya and floated tenders for its detailed project report.

BMRCL will invite tenders for 28.4-km corridor linking JP Nagar 4th Phase to Kempapura in Hebbal. Central Government approved stretch nearly a year ago; tendering delayed due to complex double-decker viaduct design combining metro line and flyover. Project divided into ten construction packages covering viaducts, stations, depots.

Corridor passes through JP Nagar, Kamakya, Kadirenahalli, Hosakerehalli, KHB Colony, Kamakshipalya, Mysuru Road, Nagarabhavi Circle, Papareddypalya, Sumanahalli Cross, Nagashettihalli, Kempapura. Will include 30 stations with seven interchange points to existing and upcoming metro routes.

India's first double-decker integrated structure: 37.12 km total (28.4-km JP Nagar–Kempapura corridor plus 8.6-km elevated section Hosahalli to Kadabagere). Estimated cost ₹9,700 crore, approved by State Cabinet September. Funding: State Government 50%, Central Government 10%, loans 40%. Overall Phase 3 project ₹15,611 crore. JICA loan ₹7,577 crore for Phase 3 including rolling stock.

Originally aimed completion 2029; now expected 2031 due to planning and tendering delays. Phase 3A (Blue Line) Sarjapur to Hebbal: 36.59 km, 14.45 km underground, 22.14 km elevated, 28 stations (11 underground, 17 elevated).