Major Rivers Flowing into the Indian Ocean: By Continent

The Indian Ocean drainage basin covers ~21M km². Here are the principal rivers by region, ranked by discharge where data exists.

Africa (West & East Coasts)

• Zambezi (2,574 km, 3,400 m³/s) – Victoria Falls, Cahora Bassa, Kariba dams.
• Limpopo (1,750 km) – Botswana, Zimbabwe, SA, Mozambique.
• Rufiji (600 km) – Tanzania, largest EAfrican outflow.
• Tana (1,000 km) – Kenya, hydro cascade (Seven Forks).
• Juba / Shebelle – Somalia/Ethiopia (endorheic in drought).
• Orange (2,200 km) – Lesotho → SA → Atlantic (technically Atlantic, but often grouped).

Asia (South & Southeast)

• Ganges–Brahmaputra–Meghna (combined 1,070,000 km², 38,000 m³/s) – world's largest delta (Sundarbans).
• Indus (3,180 km, 6,600 m³/s) – Pakistan, tarbela dam.
• Irrawaddy (2,170 km) – Myanmar, 13,000 m³/s monsoon peak.
• Salween (2,815 km) – China/Myanmar/Thailand, largely undammed.
• Mekong (4,350 km, 16,000 m³/s) – 6 countries, Tonle Sap reversal.
• Chao Phraya (372 km) – Thailand, Bangkok lifeline.
• Peninsular India (E-flowing): Godavari (1,465 km), Krishna (1,400 km), Kaveri (800 km), Mahanadi, Narmada, Tapti (W-flowing, but small Indian Ocean entry via Gulf of Khambhat).

Australia (North & West Coasts)

• Fitzroy (WA, 733 km) – largest WA outflow.
• Victoria (560 km) – NT, tidal bore.
• Daly (320 km) – NT, perennial.
• Murchison (820 km) – WA, ephemeral.
• Swan (72 km) – Perth estuary.

Madagascar

• Betsiboka (525 km) – red sediment (laterite), "bleeding" estuary.
• Mangoky (564 km) – deltaic agriculture.

Indonesia (Western Islands)

• Kapuas (1,143 km) – Borneo, longest Indonesian river.
• Mahakam (980 km) – East Kalimantan, coal/gas logistics.
• Barito (890 km) – South Kalimantan, peatlands.

Papua New Guinea

• Sepik (1,126 km) – undammed, pristine basin.
• Fly (1,050 km) – huge delta, Ok Tedi mine impacts.

Hydrologic Significance

Indian Ocean receives ~30% of global river discharge. Monsoon-driven seasonality creates extreme flood/drought cycles. Dams, diversions, and climate change are altering sediment/nutrient fluxes critical to coastal fisheries and mangroves.