The climate is tropical oceanic—that is, hot and humid but relieved by cool winds and abundant, year-round rainfall. Temperatures seldom exceed 90 °F (32 °C), and rainfall generally averages 120–140 inches (3,000–3,500 mm) a year. Heavily wooded, mountainous terrain is characteristic, and, although there are extensive plains, only those on the northern side of Guadalcanal have been developed for large-scale agriculture. As in most island groups, animal life is limited.

There are hot springs on Savo, where a volcano last erupted in the 1840s. Solomon Islands has a number of other volcanoes. For example, Tinakula in the Santa Cruz group and Kavachi, a submarine volcano near New Georgia, have erupted regularly every few years, and Simbo Island has a solfatara (a volcanic area or vent that yields only hot vapours and sulfurous gases). Earthquakes and destructive cyclones also occur regularly.

Most of the population is Melanesian (Melanesian culture). Polynesians (Polynesian culture), who form a small minority, live mainly on outlying atolls, principally Ontong Java Atoll, Bellona, Rennell Island, the Reef Islands, the Stewart Islands (Sikaiana), Tikopia, and Anuta. There are also small numbers of Chinese and Europeans and of Gilbertese from Micronesia who were resettled on Ghizo and Vaghena islands between 1955 and 1971 by British administrators seeking to alleviate overpopulation in the Gilbert Islands (now Kiribati). Almost all Solomon Islanders are Christian; most are Protestant (mainly Anglican), with smaller numbers of Roman Catholics and members of other denominations. A small minority practices traditional beliefs. More than 60 languages and dialects are spoken. English is the official language, but Pijin, an English-based Melanesian pidgin (Melanesian pidgins), is the language that is most widely used and understood. Most of the people live in small rural villages. They engage mainly in subsistence gardening, pig raising, and fishing but are also involved in the cash economy.

Civil unrest in the late 1990s and early 21st century, including a coup in 2000, led to the near-collapse of the country's economy. Damage to infrastructure on Guadalcanal resulted, disrupting transportation, commerce, and agriculture, and many enterprises were forced out of business. Earthquakes followed by a tsunami in 2007 caused further economic setbacks.

In the early 21st century the service sector employed the majority of the active workforce and contributed almost half of the country's gross domestic product. Tourism has been developed but is not a major source of income. Solomon Islands' main resources, fish and timber, have been exploited excessively, which has resulted in their depletion. Its other export products are derived from plantation crops: palm oil, copra, and cacao (the source of cocoa). China, South Korea, Japan, and Thailand are the major recipients. The chief imports are machinery, fuels, manufactured goods, and food, and Australia, Singapore, Japan, and New Zealand are the main suppliers.

The islands have significant reserves of bauxite (on Rennell Island) and phosphates (on Bellona), and some gold has been extracted on Guadalcanal. Manufacturing primarily involves the processing of coconut and other vegetable oils and of cocoa. Traditional handicrafts, including woodwork, shell inlay, mats, baskets, and shell jewelry, are made both for the tourist market and for export. The Solomon Islands dollar is the official currency; indigenous currencies (currency) such as shell money (from Malaita) and red-feather money (from Santa Cruz) are also made for use in customary transactions.

The principal airport is Honiara International Airport, although there are several airfields throughout the islands that may also serve as international points of entry. The government-owned Solomon Airlines provides domestic and regional air service. Ports handling overseas cargoes include Honiara, Tulagi (the former capital), and Gizo Harbour. Aola Bay, Viru Harbour, and Graciosa Bay are used mainly for log exports. Interisland shipping is operated both privately and by the government.

Education is not compulsory. Schools are run both by the national and provincial governments and by various churches. Many secondary schools provide practical training in fields such as agriculture and development studies. There are several teacher-training schools and a technical institute, as well as a campus of the University of the South Pacific in Honiara. Some students attend universities overseas, especially in Fiji and Papua New Guinea. There is a hospital at Honiara.

The Solomon Islands were initially settled by at least 2000 BCE—well before the archaeological record begins—probably by people of the Austronesian language group (Austronesian languages). Pottery of the Lapita culture was in use in Santa Cruz and the Reef Islands about 1500 BCE. Material dating to about 1000 BCE has also been excavated at Vatuluma Cave (Guadalcanal), on Santa Ana Island, and on the outlying islands of Anuta and Tikopia.

The first European to reach the islands was the Spanish explorer Álvaro de Mendaña de Neira in 1568. Subsequently, unjustified rumours led to the belief that he had not only found gold there but had also discovered where the biblical king Solomon obtained the gold for his temple in Jerusalem. The islands thus acquired the name Islas de Solomón. Later Spanish expeditions to the southwest Pacific in 1595 and 1606 were unable to confirm the discoveries reported by Mendaña. Geographers came to doubt the existence of the group, and it was not until the late 18th century, after further sightings by French and English navigators, that the Solomons were accurately charted. After the settlement of Sydney by the English (British Empire) in 1788, naval and commercial shipping began increasingly to pass through the Solomons' waters.

Roman Catholic missionaries (mission) failed to establish a settlement in the 1840s but did so in 1898. Anglican missionaries, who had been taking islanders to New Zealand for training since the 1850s, began to settle in the Solomons in the 1870s. Other missions arrived later.

By the late 19th century the islands were being exploited for labour to work the plantations of Fiji and other islands and of Queensland, Austl. About 30,000 labourers were recruited between 1870 and 1910. To protect their own interests, Germany and Britain divided the Solomons between them in 1886; but in 1899 Germany transferred the northern islands, except for Buka (Buka Island) and Bougainville (Bougainville Island), to Britain (which had already claimed the southern islands) in return for recognition of German claims in Western Samoa (now Samoa) and parts of Africa. The British Solomon Islands Protectorate was declared in 1893, partly in response to abuses associated with labour recruitment and partly to regulate contacts between islanders and European (colonialism, Western) settlers, but mainly to forestall a threat of annexation by France. Colonial (colonialism, Western) rule began in 1896. Although generally humane, administrators were more concerned with promoting the interests of European traders and planters than those of the islanders, and islanders were punished harshly for offenses against colonial law and order. The murder of government tax collectors by members of the Kwaio ethnic group on Malaita in 1927 was answered with a savage punitive expedition, backed by an Australian warship, that burned and looted villages and killed many of the Kwaio. Together with some of his associates, Basiana, the leader of the tax collectors' killers, was hanged, and his young sons were forced to witness the execution.

With the outbreak of World War II in the Pacific, the Japanese began occupying the protectorate early in 1942, but their advance farther southward was stopped by U.S. forces, which invaded on August 7. Fighting in the Solomons over the next 15 months was some of the most bitter in the Pacific; the long Battle of Guadalcanal (Guadalcanal, Battle of) was one of the crucial conflicts of the Pacific war. Throughout the campaign the U.S. forces and their allies were strongly supported by the islanders. After the war, because of the proximity of an airfield and the availability of flat land and of the military's buildings, Honiara on Guadalcanal became the new capital, replacing Tulagi.

Another result of the war was to stimulate political consciousness among the islanders and so inspire a nationalist movement known as Maasina Rule, which lasted from 1944 to 1952. Subsequently, in response to the worldwide movement for decolonization, the Solomons set out on the path of constitutional development. The country was formally renamed Solomon Islands in 1975, and independence was attained on July 7, 1978. Peter Kenilorea, who had helped lead Solomon Islands to independence, became its first prime minister (1978–81) and served a second term from 1984 to 1986. Solomon Mamaloni, another pre-independence leader, served as prime minister several times in the 1980s and '90s; resigning from his final term in August 1997 amid allegations of corruption, he was replaced by Bartholomew Ulufa'alu.

Economic and political instability continued through the next several years. In mid-2003 the governments of the Pacific Islands Forum formed a multinational Regional Assistance Mission to the Solomon Islands (RAMSI), led by Australia, that supplied troops to help maintain order. The country's recovery progressed slowly, supported by an influx of foreign aid, particularly from Japan, New Zealand, Australia, and the European Union. After the 2006 general election, antigovernment riots broke out and parts of Honiara were burned and looted; the new prime minister, Snyder Rini, resigned after eight days in office and was replaced by Manasseh Sogavare, who opposed the presence of RAMSI. Conflict arose between RAMSI and the government over one of the prime minister's political appointments, and Sogavare threatened to expel the multinational force. A compromise was brokered late in the year, and RAMSI remained. After Sogavare lost a no-confidence vote in 2007, Derek Sikua became prime minister. Consideration of a new constitution was ongoing; it would address provincial and ethnic tensions by changing the governmental structure to that of a federation of states.