Arabian Sea

The Arabian Sea forms a major subdivision of the northern Indian Ocean, lying between the Arabian Peninsula in the west and the Indian subcontinent in the east. It has long served as a strategic maritime corridor, supporting extensive trade networks, ecological systems, and cultural interactions across coastal regions. Its waters, basins, islands and ports have shaped the historical and economic development of several bordering nations, making it one of the most significant marine regions of the world.

Geographical Setting and Physical Characteristics

The Arabian Sea is bounded by the Arabian Peninsula, the Gulf of Aden and the Guardafui Channel on its western and south-western edges, with the Gulf of Oman and Iran to the northwest. Pakistan lies directly to the north, while India forms the eastern boundary. To the southeast it meets the Laccadive Sea, and further south-west it approaches the maritime territories of the Maldives and Somalia. This broad geographical position gives the sea a unique interface between South Asia, West Asia, and East Africa.
The sea covers a very extensive surface area and reaches notable depths in several of its troughs and basins. The maximum width spans a broad distance between the Arabian and Indian coasts. Its deepest points occur within submarine depressions such as the Alula–Fartak Trough and parts of the Arabian Basin. The Indus River is the largest river draining into the sea, bringing significant sedimentary load that contributes to the formation of the Indus Fan, one of the largest submarine fan systems in the world.
The Arabian Sea is characterised by important subsidiary gulfs. The Gulf of Aden provides a direct link to the Red Sea via the Bab el-Mandeb strait, while the Gulf of Oman connects with the Persian Gulf. Additional regional gulfs, such as the Gulf of Khambhat and Gulf of Kutch along India’s western coast, constitute important coastal features. These connections make the sea an essential maritime gateway for both commercial and geopolitical movement.

Historical Context and Trade Routes

The Arabian Sea has functioned as a major maritime route since at least the 3rd or 2nd millennium BCE, connecting ancient civilisations of the Middle East, South Asia, and East Africa. During antiquity, coastal sailing vessels exploited predictable monsoon winds to traverse the sea efficiently, facilitating exchanges of goods including spices, textiles, precious stones, metals, and agricultural products.
As overland terrain north of the Arabian Sea presented formidable challenges, combined land–sea trade routes depended heavily on maritime segments. Goods often originated in the Far East or central India, with transfer points in ancient port towns such as Bharuch. Ships then navigated past the arid coasts of present-day Iran and branched either northwards toward the Levant or southwards toward ports feeding into Red Sea channels. These routes linked to camel caravans that crossed desert hinterlands, exposing traders to challenges such as banditry and local levies.
Egyptian civilisations constructed shallow canals in antiquity to support maritime–riverine movement, with one route resembling the position of the modern Suez Canal. These early engineering works were often disrupted by changing desert conditions. Later, the commercial influence of the Kingdom of Axum extended across maritime connections through the Red Sea to the Mediterranean, further elevating the Arabian Sea’s historic significance.

Hydrography and Submarine Features

Scientific surveys completed in the twentieth century have greatly enhanced understanding of the sea’s hydrographic structure. The International Indian Ocean Expedition of 1959 initiated extensive mapping, followed by further Soviet-led bathymetric projects in the 1960s.
The northern reaches are dominated by the Indus Fan, a vast accumulation of sediments from the Indus River system. Adjacent to this lies the De Covilhao Trough, which descends steeply and separates the fan from the Oman Abyssal Plain. To the south, the Arabian Basin forms a deep expanse, bordered along its southern margin by sections of the Carlsberg Ridge. The deepest known areas lie in the Alula–Fartak Trough, which extends from the western margins of the sea into the Gulf of Aden.
Several notable seamounts rise from the seabed, particularly off the Indian west coast. These include the Raman Seamount, the Panikkar Seamount and the Wadia Guyot, commemorating prominent scientific figures. Additional features, such as the SindBad and Zheng He seamounts, illustrate the diversity of submarine topography shaped by volcanic and tectonic processes.

Coastal Regions, Islands and Basin Countries

Countries with coastlines on the Arabian Sea include Yemen, Oman, Pakistan, Iran, India and the Maldives. Each nation maintains significant maritime activity, fisheries, and port infrastructure along its respective shoreline.
The sea contains a number of major islands. Socotra, part of Yemen, is the largest and forms a small archipelago renowned for its distinctive biodiversity. Masirah Island lies off Oman’s southeast coast, while Astola Island—Pakistan’s largest offshore island—is situated near the northern Arabian Sea. India’s Lakshadweep Islands form a group of coral atolls and are among the smallest union territories of the country. The Maldives, located to the south of these atolls, share a geomorphological connection through the Chagos–Laccadive Ridge.
Temporary islands have also appeared, such as Zalzala Koh, formed after a major earthquake near Pakistan in 2013, though it submerged again within a few years due to erosional processes.

Major Ports and Maritime Infrastructure

Port infrastructure along the Arabian Sea is extensive and vital for global trade flows. India hosts several major ports including Mumbai Port, Jawaharlal Nehru Port, Kandla, Mundra, Mormugao, Kochi and the emerging Vizhinjam deep-water port. These ports support container traffic, petroleum distribution, and diverse industrial trade.
Pakistan’s coastline supports large facilities such as the Port of Karachi and Port Qasim. The Gwadar Port, strategically located near the entrance to the Persian Gulf, facilitates regional connectivity and deep-water trade.
Further west, the Port of Salalah in Oman serves as a major international trans-shipment hub, frequently used by naval and commercial vessels. Its strategic location along east–west shipping corridors contributes to high levels of maritime traffic.
These ports collectively anchor the Arabian Sea as a central node in global logistics, linking Europe, Africa, the Middle East and Asia.

Environment, Wildlife and the Oxygen Minimum Zone

The ecological character of the Arabian Sea is influenced by monsoonal cycles, coastal upwelling and nutrient transport. As a result, it supports diverse marine wildlife, including numerous species of fish, cetaceans, coral communities and plankton.
One of the most significant environmental features is its oxygen minimum zone (OMZ), one of the three largest in the world. Particularly pronounced in the Gulf of Oman, oxygen levels can fall so low as to be nearly undetectable through standard measurement techniques. Factors contributing to the OMZ include oceanographic circulation patterns, high nutrient upwelling and insufficient water mixing. Anthropogenic influences, such as untreated sewage entering coastal waters, may exacerbate the problem.
Seasonal phytoplankton blooms occur across the northern Arabian Sea, especially during winter, reflecting the influence of changing wind patterns and nutrient availability. These blooms are integral to fisheries and broader marine food webs but can also respond sensitively to climatic variations.

Climatic Change and Warming Trends

Recent scientific studies have confirmed a trend of steady warming in the Arabian Sea, attributed primarily to global climate change. Observations indicate intensification and northward movement of the summer monsoon low-level jet since the late twentieth century, altering heat distribution within the upper ocean. Enhanced downwelling and reduced southward heat transport have contributed to increased upper-ocean heat content.
Such changes affect monsoon behaviour, marine ecosystems, and climatic interactions across the broader Indian Ocean region. Warming conditions may influence the occurrence of high-intensity cyclones, which have shown increased frequency in parts of the Arabian Sea in recent decades. These climatic shifts highlight the sea’s sensitivity to global atmospheric dynamics and the importance of continued monitoring.