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Oceans / XO

Indian Ocean

Last updated: October 29, 2026

Indian Ocean: CIA World Factbook map from 2021; original boundary notes preserved.
ⓘCIA World Factbook map, February 2021 media edition. Identity reviewed; current boundaries have not been audited. visual contact sheet or original identity check; does not verify current boundaries Boundaries, place names and designations may be dated or disputed; original annotations retained. SHA-256: f99c96b64a4abf351de846b436748b5f8650c0306e23f192464884a4acc0738d. Provenance and inspection record.

Introduction

Background:1

The Indian Ocean is the third largest of the world's five ocean basins (after the Pacific Ocean and Atlantic Ocean, but larger than the Southern Ocean and Arctic Ocean). Four critically important access waterways are the Suez Canal (Egypt), Bab el Mandeb (Djibouti-Yemen), Strait of Hormuz (Iran-Oman), and Strait of Malacca (Indonesia-Malaysia). The International Hydrographic Organization decided in 2000 to delimit a fifth world ocean basin, the Southern Ocean, which removed the portion of the Indian Ocean south of 60 degrees south latitude.

Geography

Location:2

body of water between Africa, the Southern Ocean, Asia, and Australia

Geographic coordinates:3

20 00 S, 80 00 E

Area:4

total:70.56 million sq km
note:includes Andaman Sea, Arabian Sea, Bay of Bengal, Great Australian Bight, Gulf of Aden, Gulf of Oman, Mozambique Channel, Persian Gulf, Red Sea, Savu Sea, Strait of Malacca, Timor Sea, and other tributary water bodies

Area - comparative:5

almost seven times the size of the US

Coastline:6

66,526 km

Climate:7

northeast monsoon (December to April), southwest monsoon (June to October); tropical cyclones occur during May/June and October/November in the northern Indian Ocean and January/February in the southern Indian Ocean

Ocean volume:8

264 million cu km

percent of World Ocean total volume:19.8%

Major ocean currents:9

the counterclockwise Indian Ocean Gyre comprised of the southward flowing warm Agulhas and East Madagascar Currents in the west, the eastward flowing South Indian Current in the south, the northward flowing cold West Australian Current in the east, and the westward flowing South Equatorial Current in the north; a distinctive annual reversal of surface currents occurs in the northern Indian Ocean; low atmospheric pressure over southwest Asia from hot, rising, summer air results in the southwest monsoon and southwest-to-northeast winds and clockwise currents, while high pressure over northern Asia from cold, falling, winter air results in the northeast monsoon and northeast-to-southwest winds and counterclockwise currents

Bathymetry:10

continental shelf:the following are examples of features on the continental shelf of the Indian Ocean (see Figure 2):
continental shelf:Exmouth Plateau
continental shelf:Indus Canyon
continental shelf:The Swatch of No Ground/Ganges Canyon (Bay of Bengal)
continental shelf:Sunda Shelf
continental slope:the following are examples of features on the continental slope of the Indian Ocean (see Figure 2):
continental slope:Bengal Fan
continental slope:Indus Fan
abyssal plains:the following are examples of features on the abyssal plains of the Indian Ocean (see Figure 2):
abyssal plains:Arabian Basin
abyssal plains:Crozet Basin
abyssal plains:Madagascar Basin
abyssal plains:Mid-Indian Basin
abyssal plains:Mozambique Basin
abyssal plains:Wharton Basin
mid-ocean ridge:the following are examples of mid-ocean ridges on the floor of the Indian Ocean (see Figure 2):
mid-ocean ridge:Central Indian Ridge
mid-ocean ridge:Davie Ridge
mid-ocean ridge:Southeast Indian Ridge
mid-ocean ridge:Southwest Indian Ridge
undersea terrain features:the following are examples of undersea terrain features on the floor of the Indian Ocean (see Figure 2):
undersea terrain features:Andaman-Nicobar Ridge
undersea terrain features:Chagos-Laccadive Ridge
undersea terrain features:Kerguelen Plateau
undersea terrain features:Madagascar Plateau
undersea terrain features:Mascarene Plateau
undersea terrain features:Mozambique Plateau
undersea terrain features:Ninetyeast Ridge
ocean trenches:the following are examples of ocean trenches on the floor of the Indian Ocean (see Figure 2):
ocean trenches:Java/Sunda Trench (deepest point in the Indian Ocean)
atolls:the following are examples of atolls in the Indian Ocean (see Figure 2):
atolls:Bassas da India
atolls:Chagos Archipelago/Diego Garcia
atolls:Europa Island
atolls:Juan de Nova Island
atolls:Lakshadweep Islands
atolls:Maldive Islands
atolls:Seychelles

Elevation:11

highest point:sea level
lowest point:Java Trench -7,192 m unnamed deep
mean depth:-3,741 m
ocean zones:the ocean is divided into three zones based on depth and light level; sunlight entering the water may travel about 1,000 m into the oceans under the right conditions, but there is rarely any significant light below 200 m
ocean zones:euphotic zone : the upper 200 m (656 ft) is also called "sunlight" zone; only a small amount of light penetrates beyond this depth
ocean zones:dysphotic zone : between 200 m (656 ft) and 1,000 m (3,280 ft), and also called the twilight zone; the intensity of light rapidly dissipates as depth increases, and photosynthesis is no longer possible
ocean zones:aphotic zone : below 1,000 m (3,280 ft) and also called the midnight zone; sunlight does not penetrate to these depths

Natural resources:12

oil and gas fields, fish, shrimp, sand and gravel aggregates, placer deposits, polymetallic nodules

Natural hazards:13

occasional icebergs pose navigational hazard in southern reaches

Geography - note:14

major chokepoints include Bab el Mandeb, Strait of Hormuz, Strait of Malacca, southern access to the Suez Canal, and the Lombok Strait

Environment

Environmental issues:15

marine pollution from ocean dumping, improper waste disposal, and oil spills; oil pollution in Arabian Sea, Persian Gulf, and Red Sea; threats to coral reefs; loss of biodiversity; endangered marine species

Climate:16

northeast monsoon (December to April), southwest monsoon (June to October); tropical cyclones occur during May/June and October/November in the northern Indian Ocean and January/February in the southern Indian Ocean

Marine fisheries:17

the Indian Ocean fisheries are the third most important in the world, accounting for 15.5%, or 12,220,000 mt of the global catch in 2020; tuna, small pelagic fish, and shrimp are important species in these regions; the Food and Agriculture Organization delineated two fishing regions in the Indian Ocean:

Eastern Indian Ocean region (Region 57) is the most important and the fifth-largest-producing region in the world with 8.4%, or 6,590,000 mt, of the global catch in 2020; the region encompasses the waters north of 55º South latitude and east of 80º East longitude, including the Bay of Bengal and Andaman Sea, with the major producers including India (2,362,481 mt), Indonesia (1,940,558 mt), Burma (1,114,777 mt), Bangladesh (877,837 mt), and Sri Lanka (373,369 mt); the principal catches include shad, skipjack tuna, mackerel, shrimp, and sardinellas

Western Indian Ocean region (Region 51) is the world’s sixth-largest-producing region with more than 7.1% or 5,630,000 mt of the global catch in 2020; this region encompasses the waters north of 40º South latitude and west of 80º East longitude, including the western Indian Ocean, Arabian Sea, Persian Gulf, and Red Sea, as well as the waters along the east coast of Africa and Madagascar, the south coast of the Arabian Peninsula, and the west coast of India; major producers include India (2,207,125 mt), Oman (580,048 mt), Pakistan (341,730 mt), and Mozambique (274,791 mt); the principal catches include skipjack and yellowfin tuna, mackerel, sardines, shrimp, and cephalopods

Regional fisheries bodies:Indian Ocean Tuna Commission, Commission for the Conservation of Southern Bluefin Tuna, Regional Commission for Fisheries (Persian Gulf/Gulf of Oman), Southeast Asia Fisheries Development Center, Southwest Indian Ocean Fisheries Commission, South Indian Ocean Fisheries Agreement

Government

Country name:18

etymology:named for the country of India, which makes up much of its northern border

Historical observations

Notes & sources

  1. Background. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  2. Location. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  3. Geographic coordinates. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  4. Area. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  5. Area - comparative. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  6. Coastline. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  7. Climate. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  8. Ocean volume. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  9. Major ocean currents. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  10. Bathymetry. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  11. Elevation. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  12. Natural resources. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  13. Natural hazards. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  14. Geography - note. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  15. Environmental issues. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  16. Climate. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  17. Marine fisheries. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
  18. Country name. Reference edition; observation: dates as stated in text. Field last updated: not supplied; profile fallback: 2025-08-28 05:45:33 -0400 (not a field revision date); needs review. Reference source. Edition last checked 2026-10-29 (retrieval only). ↩
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