Khloe Kardashian -- Wet and Wooed By French Montana on Vacation

Khloe Kardashian is in the midst of a very wet reunion with French Montana ... and there's a good chance banging is in the forecast.

The exes are in Key West this week ... with her BFF Malika and French's homie, Chinx ... doing typical Keys stuff like jet skiing.

However, our sources tell us French greeted Khloe with a bouquet of red roses when she arrived at the resort over the weekend.

No one's saying they're totally back on yet -- but as one source put it, "I wouldn't be surprised if they fall back into old habits" while they're down there.