It has been a state visit filled with ceremony and "good mornings".
Key and wife Bronagh's faces have been beamed from large billboards at Jakarta's international airport and outside the Presidential Palace.
At the palace on Monday, media waited for three hours in the humid, lush gardens as Key was welcomed by a military parade, a 19-gun salute, hundreds of schoolchildren, and then smiled and shook hands in a series of photo opportunities.
He was at pains to highlight the immediate, tangible benefits to the trip, pointing to a major breakthrough in beef exports, and the thousands of children who will be educated as a direct result of New Zealand aid.
During a visit to a huge Fonterra factory on the outskirts of Jakarta, he described the $40 million manufacturing plant as "living proof" of NZ's growing reach into Asia.
Unfortunately for him, the flag behind his podium was that of Australia's. Minutes later, the mischievous fifth star had been covered over and Kiwi-Indonesian relations were back on track.
After a tricky couple of weeks, unsettled by housing problems at home and terror and Brexit in Europe, the Indonesia leg of Key's overseas trip appeared to be a relief.
The Prime Minister was often among mates, including Indonesian Trade Minister Thomas Lembong, also a former investment banker.
"Tom is ex-Morgan Stanley, and I am ex-Merrill Lynch," Key said.
"We won't talk too much about it, but it's fair to say Morgan Stanley is still in operation in its own right and Merrill Lynch is not. So there you go."
Despite the weighty topics on the bilateral agenda - the death penalty, the South China Sea dispute, human rights abuses - Key and Indonesian President Joko Widodo emerged from the talks with a smile.
The New Zealand-Indonesia relationship is still a work in progress. One of the NZ trade delegation says New Zealand is still not quite aware that Southeast Asia is on its doorstep. Within some age-groups, not a single person studied Bahasa Indonesia last year, yet 28 studied Level 3 Latin.
At a function for business leaders, Key is introduced in fluent Indonesian by a New Zealand official, who describes him as New Zealand's "big boss". "Sorry I don't speak Bahasa Indonesia," Key responds. "But I understood 'big boss'."
