Against the backdrop of airspace and maritime disputes in the months beforehand, and ongoing adjustments following the Pakatan Harapan coalition's surprise win last year, came the ninth Malaysia-Singapore Leaders' Retreat in April in Putrajaya.
It marked the first retreat together as heads of government for Prime Minister Lee Hsien Loong and Malaysian Prime Minister Mahathir Mohamad. The spotlight was on the meeting and what it might signal for the neighbours' relationship.
Indeed, progress was made: They reaffirmed strong economic ties and their commitment to resolve issues of concern in an amicable and constructive manner. Outstanding matters tabled included the maritime border issue, the 1962 Water Agreement, flights in the Pasir Gudang airspace and the postponement of the Kuala Lumpur-Singapore High-Speed Rail project.
PM Lee's sojourns over the year included notable visits to Indonesia for President Joko Widodo's inauguration for his second term, as well as to China and the United States.
Financial cooperation was high on the agenda when Mr Lee and Mr Joko met in Singapore for their annual leaders' retreat in October. Both countries agreed to renew a US$10 billion (S$13.6 billion) bilateral financial arrangement between the Monetary Authority of Singapore and Bank Indonesia, to support monetary and financial stability. They also agreed to boost tie-ups in the digital economy, industrial parks, tourism and infrastructure, and to strengthen the flow of trade and investments.
Farther afield, Mr Lee visited China in April to attend the second Belt and Road Forum. He met Chinese President Xi Jinping and Premier Li Keqiang to discuss the progress of government collaboration projects, as well as developments like the Regional Comprehensive Economic Partnership (RCEP). Both sides inked agreements to collaborate on trade, law enforcement and projects under the Belt and Road Initiative.
September saw Mr Lee making his first address to world leaders at the United Nations General Assembly since becoming Prime Minister in 2004. He called on them to push harder against the tide of isolationism and uphold multilateralism, and stressed the need to work together to deal with complex global problems like climate change.
He also met US President Donald Trump, and both leaders signed an amendment to the 1990 Memorandum of Understanding Regarding the US Use of Facilities in Singapore, a landmark agreement that underpinned the US' security presence in the region for almost 30 years.
Why it matters
Singapore's relationship with Indonesia strengthened substantially over Mr Joko's first term as President. His second term, which began at the end of October, is a chance to build on this and iron out longstanding bilateral issues on airspace management and military training.
With Malaysia, tourism, bilateral trade and investment remain strong. Both countries are each other's second-largest trading partner, and there is scope for companies to collaborate on the digital economy, among other areas. The challenge is to keep communication channels open, and have exchanges on mutually beneficial cooperation.
Opportunities abound to meet foreign counterparts during bilateral visits, as well as at multilateral meetings and conferences.
As Deputy Prime Minister Heng Swee Keat said at The Straits Times Global Outlook Forum last month, through these meetings, leaders develop a good personal understanding of one another so that even difficult bilateral issues can be discussed amicably. He had noted: "This is crucial because we have more common interests than differences."
Against the backdrop of anti-globalisation and anti-trade rhetoric, continued cooperation on trade pacts such as the RCEP is also important. The 10 Asean nations and five other countries - Australia, China, Japan, New Zealand and South Korea - concluded negotiations on all 20 chapters and market access issues of the RCEP trade pact earlier last month, with the intent to sign it next year.
For the Republic and its like-minded partners, such pacts help to create jobs through greater trade and investment flows. They also signal continued commitment to strengthening the rules-based multilateral trading system.
What lies ahead
Next year marks the 30th anniversary of diplomatic relations between China and Singapore, and the bilateral relations face new opportunities for development.
In addition to partnerships at the government level, companies on both sides can explore joint projects in third countries in sectors such as infrastructure, logistics, and financial and legal services.
The milestone renewal of the 1990 defence pact with the US allows American forces access to Singapore's air and naval bases for another 15 years until 2035.
Following Malaysia's request - its third - to extend the suspension of the Rapid Transit System (RTS) project, Singapore and Malaysia will need to sign three agreements by the end of next April on the cross-border RTS Link.
President Halimah Yacob is also slated to make a state visit to Indonesia. Following her meeting with Mr Joko in Singapore in October, there is room to deepen ties in areas such as trade and investments, human resource development, tourism, education and culture.