Prime Minister Justin Trudeau of Canada on Friday night landed in Florida to see President-elect Donald J. Trump at Mar-a-Lago, two officials with direct knowledge of the visit said, after a threat by Mr. Trump to impose the across-the-board tariffs on goods from Canada and Mexico on Day 1.

One official said that Mr. Trudeau was expected to stay in the area overnight Friday, but not at Mar-a-Lago.

Mr. Trudeau has been scrambling to formulate a plan to respond to the threat made earlier this week by Mr. Trump for a 25 percent tariff unless the two countries take action to curb the arrival of undocumented migrants and drugs from their borders to the United States.

Mr. Trump said he would sign such a policy on his first day in office, a move that could potentially cripple trade across the continent.

The threat was also seen as an opening salvo in what would most likely be a long renegotiation of the trade agreement among the three North American nations, known as the USMCA —United States, Mexico, Canada trade agreement, the successor to the North American Free Trade Agreement.

Mr. Trudeau has tried to project calm and confidence, saying that he believed that Mr. Trump would see that tariffs would harm both countries, which are each other’s biggest trading partners. About 80 percent of Canada’s oil and 40 percent of its gas are exported to the United States, and the two countries are deeply intertwined through the joint manufacturing of cars, as well as in multiple other industries.

The Mar-a-Lago visit on Friday, which was initially reported by the Globe and Mail news paper on the basis of tracking Mr. Trudeau’s plane, is intended as a direct effort by Mr. Trudeau to show that he has a plan to address Mr. Trump’s border concerns, and that tariffs should be avoided for the sake of both nations’ economies.

Mr. Trudeau and Mexico’s president, Claudia Sheinbaum, have taken very different approaches to Mr. Trump’s tariff threats. Mr. Trudeau and other senior Canadian officials have sought to distinguish Canada’s position from Mexico’s, highlighting that Canada is better aligned with the United States and Mr. Trump’s agenda on three key issues: the borders, restrictions on China and bringing well-paying jobs back home.

Ms. Sheinbaum has been firmer, threatening retaliatory tariffs if Mr. Trump made good on his threat.

The split has driven a wedge between two allies, Canada and Mexico, who were able to leverage their relationship to negotiate a favorable agreement during Mr. Trump’s first presidency. The trade pact is officially up for renegotiation in 2026, but analysts say they believe that Mr. Trump’s decision to put tariffs against the two U.S. neighbors on the table even before he takes office, indicates that a renegotiation of that agreement could come sooner than planned.