The Monegasque is set to enter his third campaign with the Scuderia, joined by new team-mate Carlos Sainz.
Ferrari last year endured its worst F1 season in four decades, slipping from second in the 2019 constructors' championship to sixth.
Revisions to Ferrari's power unit were touted as key contributors to that downturn in performance, a point which the team hopes has been remedied for the coming year with an all-new engine.
“I think I've never been at Ferrari as much as this season before the actual start of the season,” Leclerc said.
“We've also been doing quite a bit of tests with the old car, so I feel very ready.”
The 23-year-old, who is de facto team leader, has spent the winter looking to round off his own performances, too.
Part of that included a test outing at Fiorano, Ferrari's private test track, in late January driving the team's 2018 car.
“I still believe that tyre management is something I shall push,” Leclerc said.
“I've improved massively last year, and I hope that will be another step this year.
“That's what I've done basically; trying to look at past races, trying to understand what could we have done better as a team, as myself, in the car, and try to improve on [tyre management] especially.”
Ferrari presented its drivers and team last month, with the launch of its 2021 car set to take place this evening.