The US president said the team told him they can "make this (convention) work very easily" and there was "great enthusiasm" for it, but he made the decision considering the safety of the people.
Those delegates were to be flown to Jacksonville after voting to attend a number of in-person events planned around the city, many of them at outside venues, but those events will now be replaced with what Trump called "tele-rallies" or online events.
Trump and Republicans opted to pick up and move most convention activities from Charlotte to Jacksonville after North Carolina's governor would not commit to easing social distancing mandates for the convention. "It's hard for us to say we're going to have a lot of people packed in a room and then other people shouldn't do it".
"It's a different world, and it will be for a little while", Trump said, explaining his decision.
Events in Charlotte, North Carolina, will still be held.
The president said he spoke to Florida Gov. Ron Desantis about the decision, adding the state will "be doing very well very shortly".
Trump says coronavirus crisis will probably 'get worse before it gets better'
"We're asking everybody that when you are not able to socially distance, wear a mask, get a mask". The campaign said Trump talked remotely with a teacher from Frisco, Texas.
US President Donald Trump, a Republican who has rejected a nationwide mask rule and been reluctant to wear one himself, this week reversed course and encouraged Americans to do so.
The convention was scheduled for August but critics of the president had condemned him and the Republican party for planning a large in-person convention in a state with one of the worst increases in coronavirus.
Trump said he did not cancel the convention events at the request of local officials, but the Jacksonville City Council was set to meet Friday to discuss safety concerns around the gathering.
Trump told a White House briefing on Thursday that hot spot states may need to delay re-opening schools by a few weeks but pushed for most students to be able to return to classrooms in the fall. "I said there's nothing more important in our country than keeping our people safe, whether it's from the China virus or the radical left mob". "It's just not right with what's happened recently, the flare-up in Florida". Former Vice President Joe Biden is the nominee of the opposition Democratic party.
Jacksonville Mayor Lenny Curry, a former chair of the Florida Republican Party, said he appreciated Trump "putting health and public safety first".
The Republican National Committee Chairwoman Ronna McDaniel announced in early June that Trump will accept the Republican nomination this year in Jacksonville. The list of donors to the now-canceled event reads like a who's who of industry titans, power brokers and wealthy Republicans.