LeBron James -- The 'Mission Impossible' Wedding Invites

LeBron James has sent out his wedding invites -- problem is the nuptials are SO top secret they don't list a time or location ... but instead send invited guests on a clandestine retrieval mission.

According to the invites -- obtained by TMZ -- LeBron and Savannah Brinson are still tying the knot on the weekend of Sept.13th to 15th, somewhere in San Diego (which we knew from the Save the Date).

But the invites are super vague ... only listing a "Welcome Barbeque" at 7pm on Friday, Sept 13th (which is the beginning of Yom Kippur. Sorry Jews). Then listing a "Farewell Brunch" at 10:30 am Sunday.

THERE IS NO MENTION OF AN ADDRESS OR SATURDAY'S CEREMONY!!!!!

Instead, guests are instructed to call a top secret phone number by August 1st. After guests call the number, someone will get back to them with actual details.