When Diddy’s away, his kids will play.

Sean “Diddy” Combs’ six oldest children have been living big — and using their famous poppa’s money to do it, a source close to the embattled music mogul’s inner circle told The Post.

As Combs awaits the start of his May 5 federal criminal trial on sex trafficking and racketeering charges, his influencer offspring have been taking lavish island vacations and extravagant shopping sprees both here and abroad, said the source.

“They wanna look like ballers and project this image on Instagram and TikTok,” the source explained. “But that’s Diddy’s money. I mean, maybe he gave them permission to spend it, but I doubt it, since he’s got all these people suing him.”

Since Combs’ arrest last September, his private jet’s gotten a lot of use, making trips to California, Hawaii, Texas, Florida and several other states, as well as Mexico, Italy, India, Ireland, Canada and St. Martin, according to flight data reviewed by The Post.

“Jet fuel ain’t cheap,” said the source. “Every other day, these kids are getting on Puff’s jet, and every time they do that, it costs him thousands — just for the f–king fuel.”

Quincy, 33, Justin, 31, Christian, 26, Chance, 19, and 18-year-old twins D’Lila and Jessie are apparently not shy about sharing their luxe adventures on social media.

On his Instagram, Christian recently shared a video of him playing on an ocean beach with the youngest of Combs’ seven kids, little Love, 2. Pictures show him shopping for diamond-encrusted watches and designer jackets at luxury vintage clothing store What Goes Around Comes Around, and exiting an SUV carrying shopping bags from five high-end shops.

Other pics show him with his girlfriend, Raven Tracy, riding camels in Mexico. On her account, there are snaps showing Combs, a massive diamond chain around his neck, and Tracy at a spa, along with pics of Tracy lounging on a yacht.

Quincy also enjoyed some fun in the sun, while Chance recently rode horses along a sandy beach following a trip to an amusement park. The twins last month posted photos from their trip to St. Barts, wearing matching Christian Dior bikinis aboard a dark blue yacht.

The source told The Post that, in addition to the designer clothing and tropical vacations, they’ve been giving away cash to friends.

“When the cat’s away, what do the mice do?” the source continued. “With him waiting in jail for this trial, those kids are doing whatever.

Forbes last year estimated Diddy’s net worth at around $400 million, down from the $740 million he was worth in 2019.

After his arrest, radio programmers quickly removed Diddy’s tunes from their playlists, Billboard reported.

His royalty payments, the source said, will likely take a hit as a result.

“They’re acting like he’s been convicted already. Or he’s dead. Like he ain’t coming back. That’s the entitlement of these younger folks.”

“If the cat ever comes back, those mice are f–ked,” added the source.

Reps for Diddy and his kids did not return calls.