Bali is Indonesia's main tourist destination, with a significant rise in tourism since the 1980s. Tourism-related business makes up 80% of its economy. It is renowned for its highly developed arts, including traditional and modern dance, sculpture, painting, leather, metalworking, and music. The Indonesian International Film Festival is held every year in Bali. Other international events held in Bali include the Miss World 2013 and 2018 Annual Meetings of the International Monetary Fund and the World Bank Group. In March 2017, TripAdvisor named Bali as the world's top destination in its Traveller's Choice award.

Bali is part of the Coral Triangle, the area with the highest biodiversity of marine species especially fish and turtles. In this area alone, over 500 reef-building coral species can be found. For comparison, this is about seven times as many as in the entire Caribbean. Bali is the home of the Subak irrigation system, a UNESCO World Heritage Site. It is also home to a unified confederation of kingdoms composed of 10 traditional royal Balinese houses, each house ruling a specific geographic area. The confederation is the successor of the Bali Kingdom. The royal houses are not recognised by the government of Indonesia; however, they originated before Dutch colonisation.

Bali was inhabited around 2000 BCE by Austronesian people who migrated originally from the island of Taiwan to Southeast Asia and Oceania through Maritime Southeast Asia. Culturally and linguistically, the Balinese are closely related to the people of the Indonesian archipelago, Malaysia, the Philippines and Oceania. Stone tools dating from this time have been found near the village of Cekik in the island's west.
In ancient Bali, nine Hindu sects existed, namely Pasupata, Bhairawa, Siwa Shidanta, Vaishnava, Bodha, Brahma, Resi, Sora and Ganapatya. Each sect revered a specific deity as its personal Godhead.
Inscriptions from 896 and 911 do not mention a king, until 914, when Sri Kesarivarma is mentioned. They also reveal an independent Bali, with a distinct dialect, where Buddhism and Sivaism were practised simultaneously. Mpu Sindok's great-granddaughter, Mahendradatta (Gunapriya Dharmapatni), married the Bali king Udayana Warmadewa (Dharmodayanavarmadeva) around 989, giving birth to Airlangga around 1001. This marriage also brought more Hinduism and Javanese culture to Bali. Princess Sakalendukirana appeared in 1098. Suradhipa reigned from 1115 to 1119, and Jayasakti from 1146 until 1150. Jayapangus appears on inscriptions between 1178 and 1181, while Adikuntiketana and his son Paramesvara in 1204.

Balinese culture was strongly influenced by Indian, Chinese, and particularly Hindu culture, beginning around the 1st century AD. The name Bali dwipa ("Bali island") has been discovered from various inscriptions, including the Blanjong pillar inscription written by Sri Kesari Warmadewa in 914 AD and mentioning Walidwipa. It was during this time that the people developed their complex irrigation system subak to grow rice in wet-field cultivation. Some religious and cultural traditions still practised today can be traced to this period.

The island of Bali lies 3.2 km (2.0 mi) east of Java, and is approximately 8 degrees south of the equator. Bali and Java are separated by the Bali Strait. East to west, the island is approximately 153 km (95 mi) wide and spans approximately 112 km (70 mi) north to south; administratively it covers 5,780 km2 (2,230 sq mi), or 5,577 km2 (2,153 sq mi) without Nusa Penida District; its population density is roughly 750 people/km2 (1,900 people/sq mi).

Bali's central mountains include several peaks over 2,000 metres (6,600 feet) in elevation and active volcanoes such as Mount Batur. The highest is Mount Agung (3,031 m, 9,944 ft), known as the "mother mountain", which is an active volcano rated as one of the world's most likely sites for a massive eruption within the next 100 years. In late 2017 Mount Agung started erupting and large numbers of people were evacuated, temporarily closing the island's airport. Mountains range from centre to the eastern side, with Mount Agung the easternmost peak. Bali's volcanic nature has contributed to its exceptional fertility and its tall mountain ranges provide the high rainfall that supports the highly productive agriculture sector. South of the mountains is a broad, steadily descending area where most of Bali's large rice crop is grown. The northern side of the mountains slopes more steeply to the sea and is the main coffee-producing area of the island, along with rice, vegetables and cattle. The longest river, Ayung River, flows approximately
75 km (47 mi)

The island is surrounded by coral reefs. Beaches in the south tend to have white sand while those in the north and west have black sand. Bali has no major waterways, although the Ho River is navigable by small sampan boats. Black sand beaches between Pasut and Klatingdukuh are being developed for tourism, but apart from the seaside temple of Tanah Lot, they are not yet used for significant tourism.
Being just 8 degrees south of the equator, Bali has a fairly even climate all year round. Average year-round temperature stands at around 30 °C (86 °F) with a humidity level of about 85%.[40]

Day time temperatures at low elevations vary between 20 to 33 °C (68 to 91 °F), but the temperatures decrease significantly with increasing elevation.

The west monsoon is in place from approximately October to April, and this can bring significant rain, particularly from December to March. During the rainy season, there are comparatively fewer tourists seen in Bali. During the Easter and Christmas holidays, the weather is very unpredictable. Outside of the monsoon period, humidity is relatively low and any rain is unlikely in lowland areas.

Bali lies just to the west of the Wallace Line, and thus has a fauna that is Asian in character, with very little Australasian influence, and has more in common with Java than with Lombok. An exception is the yellow-crested cockatoo, a member of a primarily Australasian family. There are around 280 species of birds, including the critically endangered Bali myna, which is endemic. 
Until the early 20th century, Bali was home to several large mammals: the wild banteng, leopard and the endemic Bali tiger. The banteng still occurs in its domestic form, whereas leopards are found only in neighbouring Java, and the Bali tiger is extinct. The last definite record of a tiger on Bali dates from 1937, when one was shot, though the subspecies may have survived until the 1940s or 1950s.

Among the larger trees the most common are: banyan trees, jackfruit, coconuts, bamboo species, acacia trees and also endless rows of coconuts and banana species. Numerous flowers can be seen: hibiscus, frangipani, bougainvillea, poinsettia, oleander, jasmine, water lily, lotus, roses, begonias, orchids and hydrangeas exist. On higher grounds that receive more moisture, for instance around Kintamani, certain species of fern trees, mushrooms and even pine trees thrive well. Rice comes in many varieties. Other plants with agricultural value include: salak, mangosteen, corn, kintamani orange, coffee and water spinach.

Balinese and Indonesian are the most widely spoken languages in Bali, and the vast majority of Balinese people are bilingual or trilingual. The most common spoken language around the tourist areas is Indonesian, as many people in the tourist sector are not solely Balinese, but migrants from Java, Lombok, Sumatra, and other parts of Indonesia. There are several indigenous Balinese languages, but most Balinese can also use the most widely spoken option: modern common Balinese. The usage of different Balinese languages was traditionally determined by the Balinese caste system and by clan membership, but this tradition is diminishing. Kawi and Sanskrit are also commonly used by some Hindu priests in Bali, as Hindu literature was mostly written in Sanskrit.

English and Chinese are the next most common languages (and the primary foreign languages) of many Balinese, owing to the requirements of the tourism industry, as well as the English-speaking community and huge Chinese-Indonesian population. Other foreign languages, such as Japanese, Korean, French, Russian or German are often used in multilingual signs for foreign tourists.

In 1970s, the Balinese economy was largely agriculture-based in terms of both output and employment. Tourism is now the largest single industry in terms of income, and as a result, Bali is one of Indonesia's wealthiest regions. In 2003, around 80% of Bali's economy was tourism related. By end of June 2011, the rate of non-performing loans of all banks in Bali were 2.23%, lower than the average of Indonesian banking industry non-performing loan rates (about 5%). The economy, however, suffered significantly as a result of the Islamists' terrorist bombings in 2002 and 2005. The tourism industry has since recovered from these events.

The Arabica coffee production region is the highland region of Kintamani near Mount Batur. Generally, Balinese coffee is processed using the wet method. This results in a sweet, soft coffee with good consistency. Typical flavours include lemon and other citrus notes. Many coffee farmers in Kintamani are members of a traditional farming system called Subak Abian, which is based on the Hindu philosophy of "Tri Hita Karana". According to this philosophy, the three causes of happiness are good relations with God, other people, and the environment. The Subak Abian system is ideally suited to the production of fair trade and organic coffee production. Arabica coffee from Kintamani is the first product in Indonesia to request a geographical indication.