His non-appearance came on the same day that a record 195,500 new Covid-19 infections were reported in a 24-hour period in the United States, according to the John Hopkins university tally.
The summit, attended by world leaders from across the globe, is being held virtually this year because of the Covid-19 pandemic.
Critics have said Trump appeared to show little interest in the summit on Saturday.
When the event began, Trump was among the nearly two-dozen world leaders who appeared via video-conference, beaming in from the White House situation room.
But only 13 minutes after the scheduled start time, Trump was sending tweets focused on his efforts to overturn the results of the US presidential election.
A few hours later the President had departed the White House on his way to his namesake golf club outside Washington DC.
He was there when the "side event on Pandemic Preparedness" got underway, featuring remarks from German Chancellor Angela Merkel, French President Emmanuel Macron, South Korean President Moon Jae-in and other world leaders, CNN reported. Trump did not participate.
Steven Rattner, former head of Obama Auto Task Force, tweeted his disapproval saying: “He has played golf every Sat and Sun since election and now skips G-20 pandemic mtg to play. The man who said Obama played too much golf. He is cementing his position as among our very worst presidents.”
Garrett Haake, a correspondent with NBC News, tweeted: “G20 side-meeting today on pandemic prep & response just concluded. Germany's Chancellor, France's President, and Saudi Arabia's King all attended, as did other world leaders. No American was scheduled to speak, & President Trump was at his golf course for the meeting's duration”.
Donald Trump’s slow response to the Coronavirus pandemic has drawn widespread criticism and was a cornerstone of Joe Biden’s US presidential election campaign.
Donald Trump is due to join another session of the G20 on Sunday morning, according to the White House schedule. It is likely the last time Trump will meet in a summit setting with other world leaders before president elect Biden is sworn in in January.