Trump, who is the more athletic and experienced golfer of the two, has said that the experience should be "a great thing ... you get to know somebody better on a golf course than you will over lunch."
Leadbetter, who has worked with some of the best players in golf over the past 30 years, assessed the strengths and weaknesses in both Trump's and Abe's swings for Reuters after reviewing video footage at his academy headquarters at Champions Gate in Orlando, Florida.
As he ran the rule over Trump's set-up, Leadbetter said: "He addresses the ball very nicely. His feet, his knees, his hips, his shoulders ... all pretty square so it looks very good at address.
"He takes the club a little bit back on the inside, under the plane as we call it ... it reminds me a little bit of the old Raymond Floyd swing. His swing comes a little bit over the top but he then makes a great move down with his lower body ... a very athletic move.
"Now President Trump is a fine golfer, he's a good athlete who's played a lot of basketball. He's won a number of club championships ... he's a very, very good player who loves to play the game."
Trump, aged 70, has an official handicap of 2.8 and says that he has won 18 club championships over the years.
"He probably doesn't practise as much now, given the job that he is in, but he gets the club on a beautiful plane coming down," said Leadbetter, who has worked with former world number ones Nick Faldo, Nick Price and Ernie Els, and both Michelle Wie and Lydia Ko when they were teen prodigies.
"Then as he swings through, you see his lower body really unwinding, a really good extension through the ball. I really like it.
"He has a very powerful swing and there's not much to go wrong with that swing. Maybe you'd like to see the club more up on the backswing but overall he does a really good job."
The 62-year-old Abe takes the game very seriously and, according to a frequent playing partner back in Japan, he usually shoots between 90 and 100 over 18 holes.
"He sets up very comfortably over the ball, looks like he has a good grip," Leadbetter said of Abe's swing. "He has a little bit of a sway off the ball, a lot of leg movement there, I'd like to see not quite as much knee movement.
"He has a good upper body turn, maybe a touch flat but not bad. The big thing I think that Prime Minister Abe could work on is getting through the ball ... you can see how he hangs back on his right foot.
"If he gets through the ball a little bit better, I'm sure he would find he would get a bit more distance. But overall not a bad swing. He is probably somebody who plays infrequently."
As for Saturday's friendly round of golf in Palm Beach, where Trump has hinted that he and Abe are likely to be playing partners, Leadbetter said: "They should have a very good game."
(Reporting by Mark Lamport-Stokes in St. Augustine, Florida; Editing by Andrew Both)
