Let’s use some logic here. As thurifer asked you, why would you want to receive their communion? Even if
they believe it is the True Presence, it is not.
Here is an article by This Rock on why only Catholics should receive the Eucharist in Catholic parishes:
catholic.com/thisrock/2003/0302sbs.asp
So, logically, if they can’t receive here, don’t you think it is logical to conclude that we cannot receive in their churches?
Here is an article from the Pittsburgh diocese:
pittsburghcatholic.org/newsarticles_more.phtml?id=1854
Now, it stands to reason if we are expected to have the Eucharist within the context of a Catholic liturgy (including ALL Catholic churches, Byzatine et al), then the Church does not want us out communicating with protestants unless and until they are in union with us.
Finally, there is canon law.
Can. 900 ß1 The only minister who, in the person of Christ, can bring into being the sacrament of the Eucharist, is a validly ordained priest.
Now, it stands to reason that a protestant minister is generally not a validly ordained priest; or that if he is and running around as a protestant minister, he is doing it illicitly. Therefore, no Eucharist, no reception by Catholics.
However, here is the rest of the section onthe Eucharist from the 1983 Code:
Can. 908 Catholic priests are forbidden to concelebrate the Eucharist with priests or ministers of Churches or ecclesial communities which are not in full communion with the catholic Church.
If priest can’t concelebrate with protestants, then why would we be allowed to receive communion intheir churches?
Orthodox churches are a whole ‘nother kettle of fish, as they have a valid Sacrament and a valid Orders. We can, but they dont’ want to receive. They can receive in our parishes, but they don’t want to receive.