Is it a sin to partake of communion at a non-Roman Catholic Church?

[Andruschak]

One of my AA friends is getting married at a non Roman Catholic Church. An Old Catholic Church or something like that. I have been invited. Would it be a sin for me to partake of communion at this or any other non-Roman Catholic Church? What about the Orthodox Church

 

[Reginald_Plum]

Andruschak,

These links should be helpful for determining the validity of your friend’s Eucharist as it depends on which church he attends. The last one is written from the perspective of people of other churches receiving in the Catholic Church, but it is just as accurate for the other way around. Congratulations on your sobriety! If you have any further questions or concerns that are not answered by these links, please contact Catholic Answers directly.

Recommended Reading:
Is it a sin to receive communion in a Protestant church?
Should I attend an SSPX wedding? Is it valid?
Can one receive Communion from an SSPX priest?
Do Old Catholic Anglicans have apostolic succession and valid sacraments?
Can all “Catholics” receive Catholic Communion in a Roman Catholic Church?