Depends on the sort of water, I guess. Salty and oxygen-rich wouldn't be so good. I'll just leave the https://en.wikipedia.org/wiki/Antikythera_mechanism here for you to think about. That had ca. 2100 years +/-ca. 100 years of underwater seawater exposure, and look what it did to it.
What would only 10000 years more of that have done to it?