Engaged Couples Talking on the Phone Permissible?

In the Name of Allah, Most Gracious, Most Merciful.

All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:

1- During the time of engagement, the man and woman are not married, so there are certain restrictions placed on the level of interaction between them to avert any possible act of violating Shariah’s teachings and principles.

2- Thus, for instance, it’s completely forbidden for them to have intimate relations during this time. However, if engaged couples abide by Islamic morals at all levels, there is nothing wrong in having such communication on condition that they are moderate in their behavior and abide by Islamic morals in their speech.

the eminent Muslim scholar, Dr. `Abdul-Fattah `Ashoor, Professor of the Exegesis of the Qur’an at Al-Azhar University, states:
Your talk with your fiancée is like any other talk. It should not incite any sexual desires. The girl should abide by the Islamic morals governing talk that is mentioned in the Quranic verse that reads: {O you wives of the Prophet! You are not like any other women. If you keep your duty (to Allah), then be not soft of speech, lest he in whose heart is a disease aspire (to you), but utter customary speech.} (Al-Ahzab 33:32)

Your talk should be pure and moral. If you abide by these morals, then there is nothing wrong in talking to her.

Sheikh Ahmad , a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, also adds:
Engagement in Islam is simply a commitment or promise to marry at a future date or time. Its sole function and significance are to keep other suitors at bay for the time being.
There are virtually no other legal consequences that accrue from the period of engagement. Thus, engagement does not make what was otherwise considered haram (prohibited) as halal (permitted).

One, therefore, must never look at engagement as a license to engage in endless chats on the phone or exchange emails because in the Shari`ah they are still considered strangers. Failure to take this into account amounts to violating the principles of the Shari`ah.
May Allah inspire in us good thoughts and good deeds, and protect us from the evil inclinations inherent in our souls!

Allah Almighty knows best.