Ben Affleck Falls Asleep on Boat in France During J Lo Honeymoon

Ben Affleck is ready to hit the deck -- which is exactly what he did on his honeymoon ... just so he could hit the hay.

The actor was seen catching a nap on his family-style excursion with Jennifer Lopez and their respective children Saturday -- this while they cruised down the Seine River in Paris on a boat ... where they've been for the past several days enjoying their post-nuptials chapter.

As you can see, BA has no problem falling into what looks like a pretty deep sleep -- dude's literally got his feet kicked up and his head back. We can almost hear the snoring!

BTW, this comfy position wasn't the only he tried to get into dream mode -- at one point he was seen curled up in his own knees, kinda like one would do on a bus or plane. Fortunately for him, he was able to find the sweet spot toward the front of the vessel.

No sign of Jen and the kiddos here -- but that's probably for the best. Papa Bear mustn't be disturbed in situations like these ... a man's gotta get his rest, after all.