Ryan Seacrest and Vanna White Filming 'Wheel of Fortune' Promos in Hawaii

Ryan Seacrest is literally diving right into his new gig as the "Wheel of Fortune" host ... filming promos in Hawaii for the upcoming season, and going underwater.

Ryan and Vanna White are on Waikiki Beach right now on Oahu, where they are filming the Hawaii episodes for the upcoming Season 42.

In one take, Vanna and Ryan are talking to the camera as they stand in ankle-deep water ... and then Ryan, in full snorkel gear, dives under.

Imagine Pat Sajak doing this!!!

Of course, Pat's now retired and Ryan's taking the reigns ... and ya gotta imagine he's enjoying his new gig. Hard to beat on-location filming in Hawaii.

Ryan and Vanna also filmed a couple promos on land -- he's wearing flip-flops and a Hawaiian shirt as they shoot at the Hilton Hawaiian Village Waikiki Beach Resort.

Folks who were there say RS and VW seemed to have great chemistry together and were getting along between takes.

They must have been in a good mood, because they were also happily taking selfies with fans ... in that aloha spirit.