The Sharjah daily quoted Dubai's prosecutor general. Calls to the prosecutor's office were not returned Tuesday, and the U.S. Embassy in Abu Dhabi said it was aware of the case but would not comment further.
The three Americans were arrested March 12, the newspaper said. It did not identify their church.
If convicted of promoting a religion other than Islam or seeking converts, the Americans could face jail sentences of between five and 10 years.
A fourth American was reportedly arrested for allegedly arranging their entry visas into the country.
It is illegal to promote religions other than Islam in the Emirates, home to many Christian churches, Hindu temples and other non-Muslim worship places. Non-Muslims can practice their religions, but cannot proselytize.