Re: Can I download a Sims 3 Expansion pack online through EA to use with my disc version of the base Sims 3?

It depends which EP you are going to buy. If you have the latest EP on disc rather than download then you would still need to use the disc to play. Or you can uninstall the disc versions and download them through Origin to play without a disc. Just register your disc game codes through Origin and you will get the download versions available for those titles.