The former free-agent trio wore their white Heat uniforms to the welcoming bash in front of a crowd of 13,000 Miami fans at American Airlines Arena.
"It feels right," James said. "When we step on the floor, every single night, we're going to make the world know that the Heat is back."
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The event took place one day after reigning two-time MVP James announced he would be joining the Heat.
James' made-for-TV event, in which he dictated the terms of the broadcast to ESPN, attracted plenty of criticism, including a scathing letter from Cleveland Cavaliers owner Dan Gilbert who accused James of quitting on the team in last year's playoffs. James did not talk personally to the owner before making his decision.
But Cleveland's loss is Miami's gain and the Heat couldn't be happier.
James' jerseys were being sold Friday as soon as they could be taken out of the box. A line of fans formed around the arena Friday morning by fans hoping to put their names on a waiting list to buy tickets.
The switchboard at American Airlines Arena was overwhelmed for much of the day, and the 13,000 free seats for the welcoming bash were gone in an hour.
Fans lucky enough to get inside for the party chanted "Beat LA! Beat LA!" referring to dethroning the reigning NBA champion Los Angeles Lakers.
"It's going to be amazing to be on the court and to know that connection that we have," Wade said. "It's just a look, but it's time to turn it on. I feel sorry for whoever has to guard both of us."
Heat president Pat Riley was in attendance. James, Wade and Bosh sat on a stage and were interviewed about the upcoming season.
"It's still surreal, man," Wade said. "Me, Chris and 'Bron. We ready. We want to go to the gym now."
"This is surpassing a dream come true," Wade said. "You always want to put yourself in the best position possible. To have an opportunity to team up with arguably the best trio to ever play the game of basketball is amazing."
Said Bosh, "We wanted to come here, then LeBron wanted to come. Let's get it done, man. Let's get this thing going."
James will wear No. 6 instead of his usual 23. Bosh will wear No. 1 instead of No. 4
Wade said the NBA's newest star lineup can handle the hype.
"Yeah, it's going to be Hollywood down here," Wade said. "But when we step on the court, it's going to be about business. And everyone who wants to be part of this organisation is going to have to make that sacrifice."
