'Jersey Shore' Is Leaving MTV, but the Longtime Cast Is Not Retiring

"Jersey Shore" is officially leaving MTV ... but, the cast isn't ready to hang up their tanktops and tanning lotion just yet!

The reality show franchise's tenure on the network is coming to a close, TMZ has learned ... with MTV not picking up Season 9 of "Jersey Shore: Family Vacation."

While network hasn't given a reason, MTV is owned by Paramount ... which is going through a massive restructuring after agreeing to a deal last week to buy Warner Bros. for $111 billion.

According to the cast, "Jersey Shore" will still go on ... we've obtained video of them talking about the shows future.

Check out the clip ... it's a compilation of the show's biggest stars speaking directly to camera -- telling fans the more fun and messiness is on the way.

The video ends with the message, "Stay tuned to see what's next. This fam lives forever," flashing onscreen.

The OG "Jersey Shore" ran from 2009 to 2012 and led to multiple spin-offs and revivals ... from "Snooki & JWoww" and "The Pauly D Project" to "Double Shot at Love" and "Family Vacation."