If you're talking about nationality:
* Domestic - referring to one's own country.
* Native - born or produced in a particular place.
* Local - belonging to a particular place.
If you're talking about familiarity:
* Familiar - well-known, common, or easily recognized.
* Native - belonging naturally to a particular place or country.
* Indigenous - originating or occurring naturally in a particular place.
If you're talking about something new or unfamiliar:
* Known - recognized or identified.
* Familiar - well-known, common, or easily recognized.
* Native - belonging naturally to a particular place or country.
The best opposite will depend on the specific meaning of "foreign" in the context of your sentence.