President Trump Calls Biden 'Son of a B*tch' During 'Alligator Alcatraz' Tour

President Trump's got 'em LOL'in down in the Everglades, where he's holding court at his new immigrant detention center ... and dropping one-liners at his predecessor's expense.

POTUS was touring the facility dubbed "Alligator Alcatraz," when a reporter pointed out the joint is actually very comfortably air-conditioned -- but 47 blew off that remark, and instead fired off a comedic shot at former President Biden.

Doing his best Henny Youngman (Google him, kids) impression, Trump said ... "Hey, Biden wanted me in here. It didn't work out that way, but wanted me in here, that son of a b*tch."

His audience -- including DHS Secretary Kristi Noem and Florida Gov. Ron DeSantis -- ate up the punchline ... giving Prez Trump some hearty, and totally genuine, belly laughs.

Biden jabs aside, Trump was definitely feeling good about what he saw while walking around the brand new prison, which was built on an airstrip surrounded by Everglades swampland, and designed to hold up to 5,000 ICE detainees.

Critics of the facility say it will expose undocumented immigrants to cruel and unusual treatment in the Florida summer ... with the threat of swamp reptiles taking out anyone who dares to attempt escape.

But hey, it is air-conditioned ... with standup politicians comedians appearing daily.