Indonesia and Singapore enjoy warm and friendly ties. Each country state officials work closely together bilaterally, as well as at ASEAN and various international forum to advance common interests. Over the years, Indonesia and Singapore have maintained regular exchanges of high-level visits. The relations are underpinned by strong economic cooperation. In the past few years, Singapore has consistently been Indonesia's top foreign investor. Singapore and Indonesia also cooperate across a wide range of sectors, including health, defence and the environment.
The relations between Indonesia and Singapore are stemmed from both proximity and necessity. Singapore is one of the nearest neighboring country of Indonesia. The city-state nation is engulfed by Indonesian territory in west, south, and east, sandwiched between Malaysia and Indonesia. Both nations are the founders of ASEAN, the members of Non-Aligned Movement and APEC.
The relations between ancient Indonesia and Singapore dated back from the period of ancient kingdoms, the straits region was part of Srivijaya’s realm back in 7th century. The Nagarakretagama, a Javanese epic poem written in 1365 during Majapahit era, also referred to a settlement on the island called Temasek ('Sea Town' in Old Javanese, spelt Tumasik).
In the 1390s, a Palembang prince, Parameswara, fled to Temasek after being deposed by the Majapahit kingdom. During the 14th century, Singapore was caught in the struggle between Siam (now Thailand) and the Java-based Majapahit Empire for control over the Malay Peninsula. According to Sejarah Melayu, Singapore was defeated in one Majapahit attack. He ruled the island for several years, before being forced to Melaka where he founded the Sultanate of Malacca. 
In early 19th century, Singapore was under British control as Straits Settlements and later as Crown colony, while at the same period Indonesian archipelago gradually fell under control of Dutch East Indies Company and Dutch East Indies.
After the independence of Indonesia in 1945 and the separation of Singapore from Malaysia in 1965, both countries opened bilateral diplomatic ties officially on 1966. In 1967, both countries together with Thailand, Philippines and Malaysia founded ASEAN to ensure the peace and stability in the region.
Trade and commerce 
Located on the busiest sea lane in Straits of Malacca, serving as one of world's main hub, trade with and through Singapore is important for Indonesia to provide the link to trade with the rest of the world. Vice versa, Indonesian business is also important for Singapore. Trade and commerce is the main common motivation of both nations foreign relations, each counterpart are main trade partners of each other.
Indonesia-Singapore trade volume reaches S$36 billion (US$ 29.32 billion). Singapore is Indonesia's top foreign investor, with a cumulative total of US$1.14 billion in 142 projects. Trade between the two countries also hit around $68 billion in 2010. At the same time, Indonesia's non-oil and gas exports to Singapore are the highest in the region. 
Other than business purposes, Indonesian visitors attracted to Singapore mostly for shopping, city sightseeing, and island resorts with its theme parks, zoos, museums and gardens. While Singaporeans attracted to Indonesia mostly for its nature and culture, Bali and neighboring Batam island are particularly popular among Singapore visitors.
Security and counter terrorism 
On 3 October 2005, Prime Minister Lee Hsien Loong met Indonesian President Susilo Bambang Yudhoyono in Bali, just two days after the Bali bombings. They agreed to strengthen the fight against terrorism and also discussed cooperation in the fields of economy, trade and investment.
Territorial and environment issues 
Geographical proximity is also often raises frictions due to divergence of interests that could potentially be a hurdle even a interrupts bilateral relationship if not addressed immediately.
Singapore scarcity of land and spaces have led them to expanded their island through land reclamations. The materials needed for reclamation, sands and granites, are mostly imported from Indonesia. The quarry of sands from Indonesian territories has raised concern over environmental issues. 
See also 
- "Singapore – History". U.S. Library of Congress. Retrieved 18 June 2006.
- "Yudhoyono Wants More Singapore Investors". Jakarta Globe. July 22, 2011. Retrieved 23 January 2013.
- "Jumlah Kedatangan Wisatawan Mancanegara ke Indonesia Menurut Negara Tempat Tinggal 2002-2010" (in Indonesian). Statistics Indonesia (Badan Pusat Statistik). Retrieved 2011-11-06.
- "Tourism Statistics Publications". Singapore Tourism Board. Retrieved 2012-04-29.
- "Indonesia may ban granite exports". ANTARA News. 12 March 2007.
- Levitt, Tom (11th May, 2010). "The damage caused by Singapore's insatiable thirst for land". Ecologist. Retrieved 23 January 2013.
- Asha Popatlal (8 August 2005). "Singapore and Indonesia sign MOU to expand air links". Channel NewsAsia.